Horizontal Branch A- and B-type Stars in Globular Clusters

Globular clusters offer ideal laboratories to test the predictions of stellar evolution. When doing so with spectroscopic analyses during the 1990s, however, the parameters we derived for hot horizontal branch stars deviated systematically from theoretical predictions. The parameters of cooler, A-type horizontal branch stars, on the other hand, were consistent with evolutionary theories. In 1999, two groups independently suggested that diffusion effects might cause these deviations, which we verified subsequently. I will discuss these observations and analyses and their consequences for interpreting observations of hot horizontal branch stars.Comment: 8 pages, 1 figure, style files included, Invited Lecture at IAU Symposium 224 "The A Star Puzzle

The peculiar properties of horizontal branch stars in omega Centauri

We measured temperatures, gravities, and masses for a large sample of blue horizontal branch stars in omega Centauri, comparing the results with theoretical expectations for canonical and He-enriched stars, and with previous measurements in three other clusters. The measured gravities of omega Cen stars are systematically lower than canonical models, in agreement with expectations for He-enriched stars, and contrary to that observed in the comparison clusters. However, the derived masses are unrealistically too low as well. This cannot be explained by low gravities alone, nor by any of the other parameters entering in the calculation. We find that the same stars are not brighter than their analogs in the other clusters, contrary to the expectations of the He-enrichment scenario. The interpretation of the results is thus not straightforward, but they reveal an intrinsic, physical difference between HB stars in omega Cen and in the three comparison clusters.Comment: Accepted for publication in ApJ Letter

Construction skills development in the UK : transitioning between the formal and informal

Research reported here is part of a wider study that seeks to examine the practices involved in encouraging and enabling employers to engage with the skills development agenda. A series of exploratory interviews and ethnographic observations reveal potential disconnections between skills policies at the governmental level and what actually happens in employer practices regarding skills development. On the one hand, the formal education and training system focuses on such targets as the attainment of narrowly-defined occupational standards, levels of competence, and quantitative performance measures like completion rates. On the other hand, the socialised concept of skills development takes place informally at the workplace through on-the-job training and mentoring relationships between senior and junior employees. Both the formal and informal systems appear to co-exist alongside each other, although tensions are mounting in terms of confidence that employers and the wider industry place on the efficacy of the formal system

Coordination of infrastructure development : some international comparisons

This report presents the findings from a desktop review into how governments across a selection of countries coordinate infrastructure development by working with the industry. The selected countries included the UK (Northern Ireland was examined separately from mainland UK), Canada, Germany, Japan and South Korea. The goal is to identify alternative means of coordinating infrastructure development at the government level, with a view to assist the Institution of Civil Engineers to make the case for a more strategic approach to planning and delivery of infrastructure. The need for this report derives from growing complexity in the way infrastructure development programmes are procured, and the shifting role of government from provider of infrastructure development to enabler of the process of delivery. Thus, an opportunity arose to compare alternative arrangements of government coordination. There were similarities of political governance landscape between the investigated countries regarding strategies of infrastructure delivery. Differences exist however in the way resources are allocated and decisions made regarding infrastructure development. A potential for greater transparency and collaboration between public and private sector was identified. In Germany, for example, local governments enjoy a great deal of autonomy in defining infrastructural requirements, even though the definition of requirements has to align with high-level planning principles at the regional, national and European levels. Delivery of infrastructure development is devolved to the local governments working with a range of stakeholders from both the public and private sectors with funding provided by regional allocations. By contrast, infrastructure development is coordinated by a single high-level government department Canada, Japan and South Korea. The make-up of this department varies across the three countries, with subtle differences in the roles and responsibilities of each constituent part. Nonetheless, the benefits of such an approach include a whole-systems view in decision-making and a somewhat simpler, more transparent way of funding allocation. Furthermore, in the case of Japan and South Korea, resources can be more effectively channelled towards advancing research and development related to infrastructure development capacity and more clarity in terms of skills development. The UK, on the other hand, has a fragmented approach in addressing infrastructure development, with a continuously evolving system of government departments and agencies having some form of influence on determining infrastructural requirements. In order to redress some of the challenges with such fragmentation, the situation in Northern Ireland differs slightly with the formation of a Strategic Investment Board Limited charged with overseeing infrastructure programmes, making delivery more transparent

Formal and informal systems of VET: implications for employee involvement

The age-old conundrum embodied in the skills challenge is this: if it is accepted that skills are a good thing, then why is it that the uptake of skills development practices, through, for example, training and lifelong learning agenda, are not widespread? In voluntarist Britain, policy- makers, researchers, educationalists and even practitioners have been grappling for a long time with low training participation, and the low-skills, low-wage route that British industry has adopted. Problems associated with this include claims of a productivity gap that exists between the UK and major competitors and the perpetuation of short-termism that has led to the restriction of capacity development. Scholars offering a panacea to the challenge have often called for the strengthening of institutions, usually supporting such exhortations with evidence from comparative studies that other countries are better in the regulation of both internal and external labour markets. Notwithstanding the necessity to strengthen institutions and to develop a comprehensive vocational education and training (VET) system that respects social partnership and industrial democracy and genuinely involves the employee voice, there is also a need to account for the multi-layered nature that currently exists in formal and informal guises

Observations of the Hot Horizontal-Branch Stars in the Metal-Rich Bulge Globular Cluster NGC 6388 - Indications of Helium Enrichment and a Lesson in Crowded Field Spectroscopy

(abridged) The metal-rich bulge globular cluster NGC6388 shows a distinct blue horizontal-branch tail with a strong upward tilt in its colour-magnitude diagram. Several noncanonical scenarios have been proposed to explain these puzzling observations. In order to test the predictions of these scenarios, we have obtained medium resolution spectra to determine the atmospheric parameters of a sample of the blue HB stars in NGC 6388. Using the medium resolution spectra, we determine effective temperatures, surface gravities and helium abundances by fitting the observed Balmer and helium lines with appropriate theoretical stellar spectra. As we know the distance to the cluster, we can verify our results by determining masses for the stars. During the data reduction we took special care in subtracting the background, which is dominated by the overlapping spectra of cool stars. The physical parameters of the blue HB stars near 10,000 K support the helium pollution scenario. The low gravities and masses found for the hot blue tail stars, however, are probably caused by problems with the data reduction, most likely due to remaining background light in the spectra, which would affect the fainter hot blue tail stars much more strongly than the brighter cool blue tail stars. Our study of the hot blue tail stars in NGC 6388 illustrates the obstacles which are encountered when attempting to determine the atmospheric parameters of hot HB stars in very crowded fields using ground-based observations. We discuss these obstacles and offer possible solutions for future projects.Comment: 11 pages, 9 figures (finding charts as png only), uses aa.cls; accepted for publication in A&