Binaries among Ap and Am stars

The results of long-term surveys of radial velocities of cool Ap and Am stars are presented. There are two samples, one of about 100 Ap stars and the other of 86 Am stars. Both have been observed with the CORAVEL scanner from Observatoire de Haute-Provence (CNRS), France. The conspicuous lack of short-period binaries among cool Ap stars seems confirmed, although this may be the result of an observational bias; one system has a period as short as 1.6 days. A dozen new orbits could be determined, including that of one SB2 system. Considering the mass functions of 68 binaries from the literature and from our work, we conclude that the distribution of the mass ratios is the same for the Bp-Ap stars than for normal G dwarfs. Among the Am stars, we found 52 binaries, i.e. 60%; an orbit could be computed for 29 of them. Among these 29, there are 7 SB2 systems, one triple and one quadruple system. The 21 stars with an apparently constant radial velocity may show up later as long-period binaries with a high eccentricity. The mass functions of the SB1 systems are compatible with cool main-sequence companions, also suggested by ongoing spectral observations.Comment: 5 pages, 2 figures, to appear in: Proc. of the 26th workshop of the European Working Group on CP stars, Contrib. Astr. Obs. Skalnate Pleso Vol. 27, No

CNONa and 12C/13C in giants of 10 open clusters

Evolved low-mass stars of a wide range of metallicity bear signatures of a non-standard mixing event in their surface abundances of Li, C, and N, and in their 12C/13C ratio. A Na overabundance has also been reported in some giants of open clusters but remains controversial. The cause of the extra-mixing has been attributed to thermohaline convection that should take place after the RGB bump for low-mass stars and on the early-AGB for more massive objects. To track the occurrence of this process over a wide mass range, we derive in a homogeneous way the abundances of C, N, O, and Na, as well as the 12C/13C ratio in a sample of 31 giants of 10 open clusters with turn-off masses from 1.7 to 3.1 Msun. A group of first ascent red giants with M/Msun \leq 2.5 exhibits lower [N/C] ratios than those measured in clump giants of the same mass range, suggesting an additional increase in the [N/C] ratio after the first dredge-up. The sodium abundances corrected from NLTE are found to be about solar. [Na/Fe] shows a slight increase of 0.10 dex as a function of stellar mass in the 1.8 to 3.2 Msun range covered by our sample, in agreement with standard first dredge-up predictions. Our results do not support previous claims of sodium overabundances as high as +0.60 dex. An anti-correlation between 12C/13C and turn-off mass is identified and interpreted as being caused by a post-bump thermohaline mixing. Moreover, we find low 12C/13C ratios in a few intermediate-mass early-AGB stars, confirming that an extra-mixing process also operates in stars that do not experienced the RGB bump. In this case, the extra-mixing possibly acts on the early-AGB, in agreement with theoretical expectations for thermohaline mixing. [abridged]Comment: A&A accepted, revised versio

A purely geometric distance to the binary star Atlas, a member of the Pleiades

We present radial velocity and new interferometric measurements of the double star Atlas, which permit, with the addition of published interferometric data, to precisely derive the orbital parameters of the binary system and the masses of the components. The derived semi-major axis, compared with its measured angular size, allows to determine a distance to Atlas of 132+-4 pc in a purely geometrical way. Under the assumption that the location of Atlas is representative of the average distance of the cluster, we confirm the distance value generally obtained through main sequence fitting, in contradiction with the early Hipparcos result (118.3+-3.5 pc).Comment: 5 pages, 3 figures, accepted for publication in A&A Letter

The World of UCL

From its foundation in 1826, UCL embraced a progressive and pioneering spirit. It was the first university in England to admit students regardless of religion and made higher education affordable and accessible to a much broader section of society. It was also effectively the first university to welcome women on equal terms with men. From the outset UCL showed a commitment to innovative ideas and new methods of teaching and research. This book charts the history of UCL from 1826 through to the present day, highlighting its many contributions to society in Britain and around the world. It covers the expansion of the university through the growth in student numbers and institutional mergers. It documents shifts in governance throughout the years and the changing social and economic context in which UCL operated, including challenging periods of reconstruction after two World Wars. Today UCL is one of the powerhouses of research and teaching, and a truly global university. It is currently seventh in the QS World University Rankings. This completely revised and updated edition features a new chapter based on interviews with key individuals at UCL. It comes at a time of ambitious development for UCL with the establishment of an entirely new campus in East London, UCL East, and Provost Michael Arthur’s ‘UCL 2034’ strategy which aims to secure the university’s long-term future and commits UCL to delivering global impact

Cultivation of the Backwater: Weirs as a Window into Historical Ecology and Ecosystem Engineering in the Lower Columbia

This poster uses the existence of a possible fish weir feature in a backwater lake on Sauvie Island in the Lower Columbia to explore questions surrounding systems of resource cultivation and human ecosystem engineering. Multiple archaeological sites in backwater areas contain large quantities of freshwater fish remains; and use of technology such as weirs would provide an efficient method of capture. However, such facilities suggest more than capture method, when considered in the larger context of landscape use and the food systems that indigenous people were part of, as demonstrated by archaeology and oral traditions. By synthesizing information surrounding precontact cultural and subsistence use of the backwaters of the Lower Columbia through the lens of historical ecology, this project seeks to highlight the broader implications of technologies that represent components in interconnected systems of indigenous aquaculture and landscape use in this rich environment

Understanding Judicial Decision-Making: The Importance of Constraints on Non-Rational Deliberations

All of social science is based on the assumption that people act rationally, in a logical, unemotional fashion. This is true for all disciplines in social science, including both economics and law. Neoclassical price theory assumes that producers and consumers are rational actors, while the reasonable person in law is the rational cousin to the economic actor. New institutional economists were among the first scholars to examine economic issues by modifying rational choice theory. Today, a large and growing body of scholarship exhibits a willingness to modify the rationality assumption by using cognitive science, behavioral psychology, and experimental economics. This Essay shares that perspective. In the Essay, we reexamine the way judges make decisions by using contemporary theories from cognitive science and concepts from the new institutional economics

Music education in the twenty-first century: a psychological perspective

Starting from Hargreaves’ (1986a) review of the relationship between developmental psychology and music education, we characterise the mid-1980s as a point at which the different main strands of music psychology – cognitive, developmental, and social – began to unfold. We move to the present day and beyond, suggesting that a major change has been the incorporation of a social perspective: it may now make more sense to talk about the developmental social psychology of music and music education. Four levels of social influence are distinguished – the individual, the interpersonal, the institutional,and the cultural – and we suggest that the concept of identity may enable explanations of social influence at the individual level. We review some research on musical style sensitivity as an exemplar of this general approach, and conclude by applying the social–cultural perspective to current developments in music education. This gives rise to two new conceptual models: of the opportunities that are offered by music education in the twenty-first century, and the outcomes that might be derived from it