Redetermination of parameters for semi-empirical model for spallogenic He and Ne in chondrites

A semi-empirical model described previously satisfactorily reproduced a number of shielding-dependent variations in the relative production rates of spallogenic He and Ne in chondrites. However, data for cores of the Keyes and St. Severin meteorites showed a subsurface build-up in He-3 which was not predicted with the original model parameters and the model was not pursued. Renewed interest in the preatmospheric size of meteorites, spurred in part by the desirability of understanding the exposure history of the SNC meteorites, justifies redetermination of model parameters

Learning to assess in higher education: exploring the interplay of ‘formal’ and ‘informal’ learning in the academic workplace.

While there has been considerable research into HE teachers’ development and their conceptions of teaching more generally (see, for instance, Trigwell et al., 1994, Trigwell et al., 1999, Kane et al., 2002, Eley, 2006), the way in which HE staff become assessors and learn about assessment has not been widely researched. Researchers such as Knight et al. (2006) have highlighted the importance of non-/informal learning in the academic workplace, and there is conflicting evidence for the impact of more formal academic development. Research on workplace learning stresses that formal and informal dimensions of learning are intertwined, but also that formal learning opportunities have a role to play in the development of expertise (Tynjälä, 2008). This paper explores the ways in which academics learn to assess in HE. It draws on empirical data from two research projects undertaken at one UK university. The ‘assessment cultures’ project explores interrelationships between socio-cultural context and academic assessment practices. 37 interviews were conducted; 24 initial and 13 follow-up interviews. In the initial interviews lecturers described how they assess in specific modules they teach. In the follow-up interviews themes such as disciplinary and occupational background and the ways lecturers learned to assess were explored. The ‘staff learning’ project examines learning about assessment through different types of academic development: a compulsory course on assessment for new academics, a module on assessment for learning for experienced staff and a university assessment for learning network providing support and activities to its members. 31 semi-structured interviews were conducted: 17 with network members, 8 with participants of the course for new academics and 6 with participants of the course on assessment for learning. Interviewees were asked about the benefits or otherwise of the type of academic development experienced, changes in their understanding of assessment and changes in their assessment practices. Taken together, the data generated by the two projects provide insight into the complex process whereby formal and informal interact. Using data from the two projects has enabled us to extend the scope of each individual project in order to address questions which could otherwise not have been answered. It has also provided an opportunity to examine the data through the lenses of different theoretical frameworks, thus heightening our awareness for the ‘the theoretical frames of reference and methodological approaches which shape (…) [our] knowledge claims’ (Shay, p.1). The collaboration has increased our awareness for our own approaches and backgrounds and has required us to engage with each others’ theoretical and professional perspectives: that of Foucauldian post-structuralism and a focus on the discursive construction of identity with that of academic development and a focus on scholarship of teaching and learning and evaluation of academic development initiatives. It has also meant drawing on each others’ respective research backgrounds in student and teacher learning in higher education research on the one hand and workplace learning research on the other. In the critical review of student learning research which Shay refers to in her ‘think piece’, Haggis (2009) explicitly highlights the potential of the workplace learning literatures and debates for ‘thinking differently’ about higher education research. By challenging ways of knowing through collaboration, the paper intends to make a contribution to the ‘region’ (Shay, p.2). Our focus in the analysis is on the interrelationships between theoretical concepts and assessment practices. In some interviews encounters with a concept such as ‘assessment for learning’ were described as a lens which sheds light onto existing assessment practices as well as a tool which enables the development of practice. This draws attention to the importance of the discursive resources that are available to academics for talking about their practice. In addition, certain ways of learning appear to be significant both in everyday workplace practice and in academic development activities, for instance learning from and through others. Interaction with other members of staff, particularly from other disciplines, enables staff to question the taken for granted and re-think their assessment practices. The data suggest that the simple distinction between formal and informal learning in the academic workplace may be too crude and that it may therefore be difficult to evaluate or ‘prove’ the impact of formal learning opportunities. However, the findings have implications for academic development since they draws attention to the potential of specific types of ideas and learning activities to transform understandings of assessment and assessment practices. The paper will discuss the main findings as well as the benefits and challenges of working with data across two research projects with different theoretical underpinnings

Chandra Observations of Arp 220: The Nuclear Source

We present the first results from 60ks of observations of Arp 220 using the ACIS-S instrument on Chandra. We report the detection of several sources near the galaxy's nucleus, including a point source with a hard spectrum that is coincident with the western radio nucleus B. This point source is mildly absorbed (N_H ~ 3 x 10^22 cm^-2) and has an estimated luminosity of 4 x 10^40 erg/s. In addition, a fainter source may coincide with the eastern nucleus A. Extended hard X-ray emission in the vicinity raises the total estimated nuclear 2-10 keV X-ray luminosity to 1.2 x 10^41 erg/s, but we cannot rule out a hidden AGN behind columns exceeding 5 x 10^24 cm^-2. We also detect a peak of soft X-ray emission to the west of the nucleus, and a hard point source 2.5 kpc from the nucleus with a luminosity of 6 x 10^39 erg/s.Comment: Accepted for publication in Ap

Chandra Observations of Arp 220: The Nuclear Source

We present the first results from 60ks of observations of Arp 220 using the ACIS-S instrument on Chandra. We report the detection of several sources near the galaxy's nucleus, including a point source with a hard spectrum that is coincident with the western radio nucleus B. This point source is mildly absorbed (N_H ~ 3 x 10^22 cm^-2) and has an estimated luminosity of 4 x 10^40 erg/s. In addition, a fainter source may coincide with the eastern nucleus A. Extended hard X-ray emission in the vicinity raises the total estimated nuclear 2-10 keV X-ray luminosity to 1.2 x 10^41 erg/s, but we cannot rule out a hidden AGN behind columns exceeding 5 x 10^24 cm^-2. We also detect a peak of soft X-ray emission to the west of the nucleus, and a hard point source 2.5 kpc from the nucleus with a luminosity of 6 x 10^39 erg/s.Comment: Accepted for publication in Ap

On the micro mechanics of one-dimensional normal compression

Discrete-element modelling has been used to investigate the micro mechanics of one-dimensional compression. One-dimensional compression is modelled in three dimensions using an oedometer and a large number of particles, and without the use of agglomerates. The fracture of a particle is governed by the octahedral shear stress within the particle due to the multiple contacts and a Weibull distribution of strengths. Different fracture mechanisms are considered, and the influence of the distribution of fragments produced for each fracture on the global particle size distribution and the slope of the normal compression line is investigated. Using the discrete-element method, compression is related to the evolution of a fractal distribution of particles. The compression index is found to be solely a function of the strengths of the particles as a function of size

Collaborative Preference: The Role of Homophily, Multiplexity, and Advantageous Network Position across Small and Medium-sized Organizations

The purpose of this paper is to examine collaboration between individuals across organizations. While both for profit and not-for-profit organizations utilize collaborative efforts, the factors that are important for bringing individuals and businesses together for collaboration still remain somewhat unresolved. In this paper, colleague similarity, the quality of pre-existing relationships, and the relative power of the other colleague are all examined for their correlation with the desirability of collaboration with that individual. In a study of pastors of small and medium sized churches in a southwestern protestant conference, we examined these areas through the lenses of homophily theory, multiplicity theories, and network positioning theories and found support for each of our hypotheses. Implications for management as well as future research directions are also presented

Chandra Observations of Extended X-ray Emission in Arp 220

We resolve the extended X-ray emission from the prototypical ultraluminous infrared galaxy Arp 220. Extended, faint edge-brightened, soft X-ray lobes outside the optical galaxy are observed to a distance of 10 to 15 kpc on each side of the nuclear region. Bright plumes inside the optical isophotes coincide with the optical line emission and extend 11 kpc from end to end across the nucleus. The data for the plumes cannot be fit by a single temperature plasma, and display a range of temperatures from 0.2 to 1 keV. The plumes emerge from bright, diffuse circumnuclear emission in the inner 3 kpc centered on the Halpha peak, which is displaced from the radio nuclei. There is a close morphological correspondence between the Halpha and soft X-ray emission on all spatial scales. We interpret the plumes as a starburst-driven superwind, and discuss two interpretations of the emission from the lobes in the context of simulations of the merger dynamics of Arp 220.Comment: Accepted for publication in ApJ; see also astro-ph/0208477 (Paper 1

Does gender matter? A cross-national investigation of primary class-room discipline.

© 2018 Informa UK Limited, trading as Taylor & Francis GroupFewer than 15% of primary school teachers in both Germany and the UK are male. With the on-going international debate about educational performance highlighting the widening gender achievement gap between girl and boy pupils, the demand for more male teachers has become prevalent in educational discourse. Concerns have frequently been raised about the underachievement of boys, with claims that the lack of male ‘role models’ in schools has an adverse effect on boys’ academic motivation and engagement. Although previous research has examined ‘teaching’ as institutional talk, men’s linguistic behaviour in the classroom remains largely ignored, especially in regard to enacting discipline. Using empirical spoken data collected from four primary school classrooms in both the UK and in Germany, this paper examines the linguistic discipline strategies of eight male and eight female teachers using Interactional Sociolinguistics to address the question, does teacher gender matter?Peer reviewedFinal Accepted Versio

Glass ceilings and stone floors: an intersectional approach to challenges UK geographers face across the career lifecycle

While there has been a steady growth of women working in geography in UK universities since the mid-Twentieth Century, there are continuing challenges in gendered career progression and professional interactions within the contemporary discipline. These range from problems associated with employment precarity and inflexible work practices, life choices and obligations in the domestic arena, discrimination and bullying, to less tangible gendered norms and cultures in the workplace. This paper discusses these challenges and inequalities in the light of a brief overview of sector-wide statistical data on appointments by gender and career-stage and with the analysis of some 250 in-depth responses to a nationwide qualitative survey of gender and career experience in UK universities (Maddrell et al 2016). While the term ‘glass ceiling’ still has significant relevance, findings show a more complicated picture which also includes ‘stone floors’ and stumbling blocks. It also shows how career experience varies by institution and individual: challenges in career progression can be compounded by institutional protocols and intersectional factors, and vary with career stage. The intersection of early-career job precarity, reproductive decisions and associated family responsibilities were particularly highlighted in this study. These ‘pinch points’ in career development disproportionately affect, but are not limited to, female early career scholars. Early career progress may be stalled in mid-career in multi-staged promotional systems such as that in UK universities; some from minorities face compound barriers; men with caring responsibilities may face prejudice. The paper concludes with suggested strategies for change, highlighting the importance of individual university and department protocols and practices; line manager and other senior colleagues’ attitudes and leadership in creating workplaces with an equality-driven ethos and structures that allow individuals to flourish

Effect of Applied Biosolids to Bahiagrass Pastures on Copper Status of Cattle

When grazing ruminants consume forages high in Mo but adequate in S, there is a risk of molybdenosis (a Mo-induced Cu deficiency). This occurs when Mo, S, and Cu join to form Cu-thiomolybdate complexes in the rumen that are not readily absorbed (Suttle, 1991). High dietary S reduces Cu absorption, possibly due to unabsorbable Cu sulphide formation, independent from its part in thiomolybdate complexes. The use of municipal sludge (biosolids) as a pasture fertiliser is of interest since some contain high Mo which may induce Cu deficiency. The objective of this study was to evaluate the performance and Cu status of cattle grazing pastures fertilized with biosolids