The Search for Low-mass Companions of B Stars in the Carina Nebula Cluster Trumpler 16

We have developed lists of likely B3--A0 stars (called "late B" stars) in the young cluster Trumpler 16. The following criteria were used: location within 3' of Eta Car, an appropriate V and B-V combination, and proper motion (where available). Color and magnitude cuts have been made assuming an E(B-V) =0.55 mag +/- 0.1, which is a good approximation close to the center of Trumpler 16. These lists have been cross-correlated with X-ray sources found in the Chandra Carina Complex Project (CCCP). Previous studies have shown that only very rarely (if at all) do late main sequence B stars produce X-rays. We present evidence that the X-ray detected sources are binaries with low-mass companions, since stars less massive than 1.4 Msun are strong X-ray sources at the age of the cluster. Both the median X-ray energies and X-ray luminosities of these sources are in good agreement with values for typical low-mass coronal X-ray sources. We find that 39% of the late B stars based on a list with proper motions have low-mass companions. Similarly, 32% of a sample without proper motions have low-mass companions. We discuss the X-ray detection completeness. These results on low-mass companions of intermediate mass stars are complementary to spectroscopic and interferometric results, and probe new parameter space of low mass companions at all separations. They do not support a steeply rising distribution of mass ratios to low masses for intermediate-mass (5 Msun) primaries, such as would be found by random pairing from the Initial Mass Function.Comment: Accepted for the ApJS Special Issue on the Chandra Carina Complex Project (CCCP), scheduled for publication in May 2011. All 16 CCCP Special Issue papers are available at http://cochise.astro.psu.edu/Carina_public/special_issue.html through 2011 at leas

Carina OB Stars: X-ray Signatures of Wind Shocks and Magnetic Fields

The Chandra Carina Complex contains 200 known O- and B type stars. The Chandra survey detected 68 of the 70 O stars and 61 of 127 known B0-B3 stars. We have assembled a publicly available optical/X-ray database to identify OB stars that depart from the canonical Lx/Lbol relation, or whose average X-ray temperatures exceed 1 keV. Among the single O stars with high kT we identify two candidate magnetically confined wind shock sources: Tr16-22, O8.5 V, and LS 1865, O8.5 V((f)). The O4 III(fc) star HD 93250 exhibits strong, hard, variable X-rays, suggesting it may be a massive binary with a period of >30 days. The visual O2 If* binary HD 93129A shows soft 0.6 keV and hard 1.9 keV emission components, suggesting embedded wind shocks close to the O2 If* Aa primary, and colliding wind shocks between Aa and Ab. Of the 11 known O-type spectroscopic binaries, the long orbital-period systems HD 93343, HD 93403 and QZ Car have higher shock temperatures than short-period systems such as HD 93205 and FO 15. Although the X-rays from most B stars may be produced in the coronae of unseen, low-mass pre-main-sequence companions, a dozen B stars with high Lx cannot be explained by a distribution of unseen companions. One of these, SS73 24 in the Treasure Chest cluster, is a new candidate Herbig Be star.Comment: To be published in a special issue of the Astrophysical Journal Supplement on the Chandra Carina Complex Projec

An Introduction to the Chandra Carina Complex Project

The Great Nebula in Carina provides an exceptional view into the violent massive star formation and feedback that typifies giant HII regions and starburst galaxies. We have mapped the Carina star-forming complex in X-rays, using archival Chandra data and a mosaic of 20 new 60ks pointings using the Chandra X-ray Observatory's Advanced CCD Imaging Spectrometer, as a testbed for understanding recent and ongoing star formation and to probe Carina's regions of bright diffuse X-ray emission. This study has yielded a catalog of properties of >14,000 X-ray point sources; >9800 of them have multiwavelength counterparts. Using Chandra's unsurpassed X-ray spatial resolution, we have separated these point sources from the extensive, spatially-complex diffuse emission that pervades the region; X-ray properties of this diffuse emission suggest that it traces feedback from Carina's massive stars. In this introductory paper, we motivate the survey design, describe the Chandra observations, and present some simple results, providing a foundation for the 15 papers that follow in this Special Issue and that present detailed catalogs, methods, and science results.Comment: Accepted for the ApJS Special Issue on the Chandra Carina Complex Project (CCCP), scheduled for publication in May 2011. All 16 CCCP Special Issue papers are available at http://cochise.astro.psu.edu/Carina_public/special_issue.html through 2011 at least. 43 pages; 18 figure

Priorities for synthesis research in ecology and environmental science

ACKNOWLEDGMENTS We thank the National Science Foundation grant #1940692 for financial support for this workshop, and the National Center for Ecological Analysis and Synthesis (NCEAS) and its staff for logistical support.Peer reviewedPublisher PD

Priorities for synthesis research in ecology and environmental science

ACKNOWLEDGMENTS We thank the National Science Foundation grant #1940692 for financial support for this workshop, and the National Center for Ecological Analysis and Synthesis (NCEAS) and its staff for logistical support.Peer reviewedPublisher PD

Aisance à l'oral en langue première, mémoire de travail et mémoire phonologique dans le développement de l'aisance à l'oral en langue seconde chez de jeunes francophones en contexte d'apprentissage intensif de la langue seconde

À l’aide d’une tâche monologique et d’une tâche dialogique, cette étude s’intéresse à la contribution de la L2 au début d’un programme, de la L1, de la MdT et de la MP au développement de l’AO en L2 chez de jeunes apprenants de l’anglais L2 (n = 47) dans le cadre d’un programme intensif de 10 mois. Les résultats montrent que seul le débit de parole en entrevue en L1 et l’AO en L2 au T1 prédisent une partie significative du développement de l’AO en L2. Les contributions varient en fonction de la tâche et de la mesure temporelle. Mots clés: Aisance langagière, aisance à l’oral, langue première, langue seconde, acquisition d’une langue seconde, mémoire de travail, mémoire phonologique, tâche monologique, tâche dialogique, contexte d’apprentissage intensif, anglais intensifUsing monologic and dialogic oral tasks, this study tracked the relative contributions that English learners’ (n = 47) L1 and initial L2 fluency skill, as well as WM and PM made to L2 fluency development over a nine-month study period. Results showed that L1 speech rate in the dialogic task and L2 fluency at T1 predicted improvement in L2 fluency, but contributions varied as a function of task type and speech measure. Keywords : L1 fluency, L2 fluency, oral fluency, second language acquisition, working memory, phonological memory, dialogic task, monologic task, intensive learning settings, formal instruction, intensive Englis

Nouvelle gouvernance rurale, dynamique des acteurs et cohabitation de la production porcine études de cas dans quatre communautés au Bas-Saint-Laurent

Les conditions d'une « bonne gouvernance» ne sont pas réunies a priori: elles doivent être en partie construites. La gouvernance est une notion en VOle de conceptualisation et on se doit d'apporter la preuve de son intérêt théorique et de sa fécondité dans les recherches empiriques. Ce défi de la nouvelle gouvernance rurale soulève des questionnements concernant l' avenir de nos communautés rurales, c'est-à-dire la façon dont les décisions doivent être prises et comment la gouvernance peut contribuer au développement de nos communautés. En somme, l'avenir des communautés rurales de petite taille semble lié à une nouvelle approche qui ne peut reposer uniquement sur une solution institutionnelle. Une des solutions possibles consiste à mettre en application le modèle de la nouvelle gouvernance rurale. Ce modèle n'a donné lieu à aucune vérification empirique dans les petites communautés rurales au Québec et offre un cadre propice pour le faire dans le contexte de la production porcine. Notre recherche permettra d'identifier des moyens de renforcer les capacités de gouvernance rurale afin de favoriser la cohabitation harmonieuse de la production porcine et de trouver une solution acceptable dans le milieu. Dans le cadre de notre mémoire, nous effectuerons une recherche dans quatre communautés dans la région du Bas-Saint-Laurent au Québec

Zdalna nauka języków: problemy, przeszkody i sukcesy

The COVID-19 pandemic forced countless colleges and universities worldwide to switch to online teaching, and many language instructors delivered their course content the usual way but remotely. This synchronous solution was motivated by the urgency of the situation but also by the common belief that languages cannot be learned efficiently without the simultaneous presence of the teacher and other learners. However, new technologies at our disposal increasingly dispel this myth by rendering asynchronous language teaching very efficient despite a few challenges. This paper presents data from Université TÉLUQ, the world's oldest French-speaking distance university, offering remote language courses for more than 40 years in a minority setting, namely a French-speaking province in English-speaking North America. We present challenges posed by teaching asynchronously in remote settings and various solutions to circumvent or overcome these challenges.Pandemia COVID-19 zmusiła niezliczone uczelnie i uniwersytety na całym świecie do przejścia na nauczanie zdalne, a wielu nauczycieli językowa prowadziło swoje kursy w zwykły sposób, choć zdalnie. To synchroniczne rozwiązanie było motywowane pilnością sytuacji, ale także powszechnym przekonaniem, że języków nie można efektywnie uczyć się bez jednoczesnej obecności nauczyciela i innych uczniów. Jednak nowe technologie, którymi dysponujemy, w coraz większym stopniu obalają ten mit, sprawiając, że asynchroniczne nauczanie języków jest bardzo wydajne pomimo szeregu wyzwań. Niniejszy artykuł przedstawia dane z Université TÉLUQ, najstarszego na świecie francuskojęzycznego uniwersytetu, gdzie nauczanie prowadzone jest na odległość, od ponad 40 lat oferującego zdalne kursy językowe w środowisku mniejszości, a mianowicie we francuskojęzycznej prowincji, która znajduje się w anglojęzycznej Ameryce Północnej. Przedstawiamy wyzwania stawiane przez nauczanie asynchroniczne w systemie zdalnym oraz różne rozwiązania mające na celu obejście lub przezwyciężenie tych wyzwań