1,179 research outputs found

    Simulations of the OzDES AGN Reverberation Mapping Project

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    As part of the OzDES spectroscopic survey we are carrying out a large scale reverberation mapping study of \sim500 quasars over five years in the 30 deg2^2 area of the Dark Energy Survey (DES) supernova fields. These quasars have redshifts ranging up to 4 and have apparent AB magnitudes between 16.8<r<22.516.8<r<22.5 mag. The aim of the survey is to measure time lags between fluctuations in the quasar continuum and broad emission line fluxes of individual objects in order to measure black hole masses for a broad range of AGN and constrain the radius-luminosity (RLR-L) relationship. Here we investigate the expected efficiency of the OzDES reverberation mapping campaign and its possible extensions. We expect to recover lags for \sim35-45\% of the quasars. AGN with shorter lags and greater variability are more likely to yield a lag, and objects with lags \lesssim6 months or \sim1 year are expected be recovered the most accurately. The baseline OzDES reverberation mapping campaign is predicted to produce an unbiased measurement of the RLR-L relationship parameters for Hβ\beta, Mg II λ\lambda2798, and C IV λ\lambda1549. However, extending the baseline survey by either increasing the spectroscopic cadence, extending the survey season, or improving the emission line flux measurement accuracy will significantly improve the RLR-L parameter constraints for all broad emission lines.Comment: Published online in MNRAS. 28 page

    Viewers base estimates of face matching accuracy on their own familiarity: Explaining the photo-ID paradox

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    Matching two different images of a face is a very easy task for familiar viewers, but much harder for unfamiliar viewers. Despite this, use of photo-ID is widespread, and people appear not to know how unreliable it is. We present a series of experiments investigating bias both when performing a matching task and when predicting other people’s performance. Participants saw pairs of faces and were asked to make a same/different judgement, after which they were asked to predict how well other people, unfamiliar with these faces, would perform. In four experiments we show different groups of participants familiar and unfamiliar faces, manipulating this in different ways: celebrities in experiments 1 to 3 and personally familiar faces in experiment 4. The results consistently show that people match images of familiar faces more accurately than unfamiliar faces. However, people also reliably predict that the faces they themselves know will be more accurately matched by different viewers. This bias is discussed in the context of current theoretical debates about face recognition, and we suggest that it may underlie the continued use of photo-ID, despite the availability of evidence about its unreliability

    A Landman’s Work Is the Foundation for Accurately Determining Mineral Ownership Under Rights-Of-Way: So, How Should a Landman Search for Roadway Title?

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    This Article addresses the many legal and practical issues a landman faces when researching title records to form a complete chain of title for roadways. Because the examining attorney reviews this chain of title to form an opinion, attorneys should understand the research process used by the landman. Further, many attorneys perform stand-up opinions from their own title research at the courthouse. Therefore, to determine whether a chain of title for a roadway is complete, the attorney must understand the title research process. Although the practical issues addressed in this Article apply more to professionals working in the urban area of the Barnett Shale play, the legal principles addressed here are equally applicable to landmen and attorneys working together in rural areas as well. Further, although the concepts discussed here may apply to several types of rights-ofway besides roads, this Article discusses these concepts in the context of roads only. This Article examines the following subjects as practiced in Texas: a brief overview of the title examination process, the process of a standard title search, and right-of-way mineral ownership law. Further, this Article analyzes each subject to suggest a legal standard, which the Texas courts have not yet articulated, for developing a chain of title that covers mineral ownership of roadways

    Antimicrobial efficacy against Pseudomonas aeruginosa biofilm formation in a three-dimensional lung epithelial model and the influence of fetal bovine serum

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    In vitro models that mimic in vivo host-pathogen interactions are needed to evaluate candidate drugs that inhibit bacterial virulence traits. We established a new approach to study Pseudomonas aeruginosa biofilm susceptibility on biotic surfaces, using a three-dimensional (3-D) lung epithelial cell model. P. aeruginosa formed antibiotic resistant biofilms on 3-D cells without affecting cell viability. The biofilm-inhibitory activity of antibiotics and/or the anti-biofilm peptide DJK-5 were evaluated on 3-D cells compared to a plastic surface, in medium with and without fetal bovine serum (FBS). In both media, aminoglycosides were more efficacious in the 3-D cell model. In serum-free medium, most antibiotics (except polymyxins) showed enhanced efficacy when 3-D cells were present. In medium with FBS, colistin was less efficacious in the 3-D cell model. DJK-5 exerted potent inhibition of P. aeruginosa association with both substrates, only in serum-free medium. DJK-5 showed stronger inhibitory activity against P. aeruginosa associated with plastic compared to 3-D cells. The combined addition of tobramycin and DJK-5 exhibited more potent ability to inhibit P. aeruginosa association with both substrates. In conclusion, lung epithelial cells influence the efficacy of most antimicrobials against P. aeruginosa biofilm formation, which in turn depends on the presence or absence of FBS

    Cultural mosaics, social structure, and identity: The Acheulean threshold in Europe

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    The period between 600 and 400 ka is a critical phase for human evolution in Europe. The south and northwest saw a dramatic increase in sites, the spread of handaxe technology alongside bone and wooden tool manufacture, efficient hunting techniques, and the use of fire. Lithic assemblages show considerable variation, including the presence/absence of handaxes and tool morphology. To explain this variation, we propose the Cultural Mosaic Model, which suggests that there is a range of expressions of the Acheulean, with local resources being instrumental in creating distinct material cultures with or without handaxes. We argue that if typologically and technologically distinct assemblage types are regionally distributed, chronologically separated, and persistent over time, then they are unlikely to be caused purely by raw material constraints or functional variation but rather reflect populations with different material cultures. We initially assess the model using British data. Britain was a northwestern peninsula of Europe, and oscillations in climate led to episodic occupation. The terraces of the pre-MIS 12 Bytham River provide a framework for dating occupation to MIS 13 and 15, while during MIS 11, archaeological sites with rich environmental records can be dated to substage level. We suggest there are six chronologically and typologically distinct assemblage types that reflect a series of population incursions into Britain. We review the broader European lithic record, which is consistent with the Cultural Mosaic Model. In developing the model, we suggest that during stable climate, localized cultures developed, while climatic change led to shifts in population, with increased knowledge exchange and gene flow. We suggest that group expression through material culture was an important stage in social development by promoting group cohesion, larger group size, better cooperation, improved knowledge transfer, and enabling populations to survive in larger foraging territories in northern Europe

    Owning Maine’s Future: Fostering a Cooperative Economy in Maine

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    Maine’s economy faces a host of well-known challenges: reliance on natural resource extraction or low-quality service jobs, geographic isolation, challenging climate, and out-migration, especially of young adults. Staying on this course is undesirable, but traditional economic development fixes have had limited success. The authors examine the possibilities of making cooperatively owned businesses a central feature of Maine’s economy. They outline the characteristics, benefits, and challenges of cooperatives and identify six important sectors of the Maine economy in which cooperative ownership already plays an important role or could make more contributions to economic and community vitality. The authors describe several other regions, with a focus on Finland, with strong cooperative economies or businesses, and examine the socioeconomic benefits and institutional features that encourage the development of cooperatives. The article concludes with policy recommendations that could facilitate similar outcomes in Maine

    The WiggleZ Dark Energy Survey: Survey Design and First Data Release

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    The WiggleZ Dark Energy Survey is a survey of 240,000 emission line galaxies in the distant universe, measured with the AAOmega spectrograph on the 3.9-m Anglo-Australian Telescope (AAT). The target galaxies are selected using ultraviolet photometry from the GALEX satellite, with a flux limit of NUV<22.8 mag. The redshift range containing 90% of the galaxies is 0.2<z<1.0. The primary aim of the survey is to precisely measure the scale of baryon acoustic oscillations (BAO) imprinted on the spatial distribution of these galaxies at look-back times of 4-8 Gyrs. Detailed forecasts indicate the survey will measure the BAO scale to better than 2% and the tangential and radial acoustic wave scales to approximately 3% and 5%, respectively. This paper provides a detailed description of the survey and its design, as well as the spectroscopic observations, data reduction, and redshift measurement techniques employed. It also presents an analysis of the properties of the target galaxies, including emission line diagnostics which show that they are mostly extreme starburst galaxies, and Hubble Space Telescope images, which show they contain a high fraction of interacting or distorted systems. In conjunction with this paper, we make a public data release of data for the first 100,000 galaxies measured for the project.Comment: Accepted by MNRAS; this has some figures in low resolution format. Full resolution PDF version (7MB) available at http://www.physics.uq.edu.au/people/mjd/pub/wigglez1.pdf The WiggleZ home page is at http://wigglez.swin.edu.au

    Mid-IR Luminosities and UV/Optical Star Formation Rates at z<1.4

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    UV continuum and mid-IR emission constitute two widely used star formation indicators at intermediate and high redshifts. We study 2430 galaxies with z<1.4 in the Extended Groth Strip with MIPS 24 mic observations from FIDEL, spectroscopy from DEEP2, and UV, optical, and near-IR photometry from AEGIS. The data are coupled with stellar population models and Bayesian SED fitting to estimate dust-corrected SFRs. In order to probe the dust heating from stellar populations of various ages, the derived SFRs were averaged over various timescales--from 100 Myr for "current" SFR to 1--3 Gyr for long-timescale SFRs. These SED-based UV/optical SFRs are compared to total infrared luminosities extrapolated from 24 mic observations. We find that for the blue, actively star forming galaxies the correlation between the IR luminosity and the UV/optical SFR shows a decrease in scatter when going from shorter to longer SFR-averaging timescales. We interpret this as the greater role of intermediate age stellar populations in heating the dust than what is typically assumed. This holds over the entire redshift range. Many so-called green valley galaxies are simply dust-obscured actively star-forming galaxies. However, there exist 24 mic-detected galaxies, some with L>10^11 L_sun, yet with little current star formation. For them a reasonable amount of dust absorption of stellar light is sufficient to produce the observed levels of IR. In our sample optical and X-ray AGNs do not contribute on average more than ~50% to the mid-IR luminosity, and we see no evidence for a large population of "IR excess" galaxies (Abridged).Comment: Accepted for publication in ApJ. Content identical to arXiv version 1. No color figure

    'Policing Rural Communities in North America': An International Society for the Study of Rural Crime Roundtable

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    Rural crime and criminal justice practices and responses face different challenges from those experienced in urban contexts. A practitioner-focused roundtable, convened by The International Society for the Study of Rural Crime (www.issrc.net), investigated challenges and innovations in international contexts on issues surrounding rural policing with a specific focus on rural policing in Canada and the United States. The roundtable was held online on 15 September 2021 and was moderated by Dr. Jessica Peterson, formerly of the University of Nebraska at Kearney (now an Assistant Professor at Southern Oregon University). Panellists were asked to respond to three key questions: What is the key element to successful community policing in your community? What is one initiative in which you have successfully engaged the community in crime-reduction efforts? What is the most significant challenge to successfully reducing crime in your community? The following are transcripts of the four presentations from the panelists on this Roundtable
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