Measuring Galaxy Environments with Deep Redshift Surveys

We study the applicability of several galaxy environment measures (n^th-nearest-neighbor distance, counts in an aperture, and Voronoi volume) within deep redshift surveys. Mock galaxy catalogs are employed to mimic representative photometric and spectroscopic surveys at high redshift (z ~ 1). We investigate the effects of survey edges, redshift precision, redshift-space distortions, and target selection upon each environment measure. We find that even optimistic photometric redshift errors (\sigma_z = 0.02) smear out the line-of-sight galaxy distribution irretrievably on small scales; this significantly limits the application of photometric redshift surveys to environment studies. Edges and holes in a survey field dramatically affect the estimation of environment, with the impact of edge effects depending upon the adopted environment measure. These edge effects considerably limit the usefulness of smaller survey fields (e.g. the GOODS fields) for studies of galaxy environment. In even the poorest groups and clusters, redshift-space distortions limit the effectiveness of each environment statistic; measuring density in projection (e.g. using counts in a cylindrical aperture or a projected n^th-nearest-neighbor distance measure) significantly improves the accuracy of measures in such over-dense environments. For the DEEP2 Galaxy Redshift Survey, we conclude that among the environment estimators tested the projected n^th-nearest-neighbor distance measure provides the most accurate estimate of local galaxy density over a continuous and broad range of scales.Comment: 17 pages including 16 figures, accepted to Ap

The Cepheid distance to the maser-host galaxy NGC 4258: Studying systematics with the Large Binocular Telescope

We identify and phase a sample of 81 Cepheids in the maser-host galaxy NGC 4258 using the Large Binocular Telescope (LBT), and obtain calibrated mean magnitudes in up to 4 filters for a subset of 43 Cepheids using archival HST data. We employ 3 models to study the systematic effects of extinction, the assumed extinction law, and metallicity on the Cepheid distance to NGC 4258. We find a correction to the Cepheid colors consistent with a grayer extinction law in NGC 4258 compared to the Milky Way ($R_V =4.9$), although we believe this is indicative of other systematic effects. If we combine our Cepheid sample with previously known Cepheids, we find a significant metallicity adjustment to the distance modulus of $\gamma_1 = -0.61 \pm 0.21$ mag/dex, for the Zaritsky et al. (1994) metallicity scale, as well as a weak trend of Cepheid colors with metallicity. Conclusions about the absolute effect of metallicity on Cepheid mean magnitudes appear to be limited by the available data on the metallicity gradient in NGC 4258, but our Cepheid data require at least some metallicity adjustment to make the Cepheid distance consistent with independent distances to the LMC and NGC 4258. From our ensemble of models and the geometric maser distance of NGC 4258 ($\mu_{N4258} = 29.40 \pm 0.06$ mag), we estimate $\mu_{LMC} = 18.57 \pm 0.14$ mag ($51.82 \pm 3.23$ kpc).Comment: Accepted for publication in MNRAS. 28 pages, 13 figures, 11 tables. A brief video summarizing the key results of this paper can be found at http://youtu.be/ICTTNyxZ89

A Powerful New Quantitative Genetics Platform, Combining Caenorhabditis elegans High-Throughput Fitness Assays with a Large Collection of Recombinant Strains.

The genetic variants underlying complex traits are often elusive even in powerful model organisms such as Caenorhabditis elegans with controlled genetic backgrounds and environmental conditions. Two major contributing factors are: (1) the lack of statistical power from measuring the phenotypes of small numbers of individuals, and (2) the use of phenotyping platforms that do not scale to hundreds of individuals and are prone to noisy measurements. Here, we generated a new resource of 359 recombinant inbred strains that augments the existing C. elegans N2xCB4856 recombinant inbred advanced intercross line population. This new strain collection removes variation in the neuropeptide receptor gene npr-1, known to have large physiological and behavioral effects on C. elegans and mitigates the hybrid strain incompatibility caused by zeel-1 and peel-1, allowing for identification of quantitative trait loci that otherwise would have been masked by those effects. Additionally, we optimized highly scalable and accurate high-throughput assays of fecundity and body size using the COPAS BIOSORT large particle nematode sorter. Using these assays, we identified quantitative trait loci involved in fecundity and growth under normal growth conditions and after exposure to the herbicide paraquat, including independent genetic loci that regulate different stages of larval growth. Our results offer a powerful platform for the discovery of the genetic variants that control differences in responses to drugs, other aqueous compounds, bacterial foods, and pathogenic stresses

The emerging landscape of reimbursement of regenerative medicine products in the UK: publications, policies and politics

Aims This paper aims to map the trends and analyse key institutional dynamics that are constituting the policies for reimbursement of Regenerative Medicine (RM), especially in the UK. Materials & Methods Two quantitative publications studies using Google Scholar and a qualitative study based on a larger study of 43 semi- structured interviews. Results Reimbursement has been a growing topic of publications specific to RM and independent from orphan drugs. Risk- sharing schemes receive attention amongst others for dealing with RM reimbursement. Trade organisations have been especially involved on RM reimbursement issues and have proposed solutions. Conclusion The policy and institutional landscape of reimbursement studies in RM is a highly variegated and conflictual one and in its infancy

Facharztweiterbildung Psychiatrie und Psychotherapie: Problemorientiertes Lernen - Evaluation eines Modellprojekts

Zusammenfassung: Die Betonung individueller Lernbedürfnisse, der Fähigkeit zur Lösung komplexer klinischer Probleme sowie einer von interkollegialer Kommunikation geprägten professionellen Grundhaltung durch das problemorientierte Lernen (POL) spricht für dessen Eignung als didaktisches Format in der Facharztweiterbildung. Dennoch wurde es bisher selten hierfür eingesetzt. Im Rahmen dieses Modellprojektes wurde das POL in das Kurrikulum der strukturierten Facharztweiterbildung Psychiatrie und Psychotherapie aufgenommen und über einen Zeitraum von 12Monaten mittels strukturierter Fragebögen evaluiert. Es fanden im Evaluationszeitraum 41POL-Kurse statt, an denen insgesamt 447 Assistenzärzte teilnahmen. Die Teilnehmer und die Tutoren bewerteten 19 von 21 erfragten Aspekten der POL-Kurse als gut bis sehr gut (Mittelwert auf einer 5-stufigen Likert-Skala >4). Insgesamt wurde das POL als besonders geeignet für die Weiterbildung eingeschätzt (Teilnehmer 4,5±0,8; Tutoren 5,0±0,2). Die Ergebnisse dieses Modellprojekts sprechen für die Eignung des POL als Teil eines vielfältigen Weiterbildungsangebots, um den Praxisbezug und die Anwendbarkeit des Wissens im klinischen Alltag zu stärke