An H alpha Survey of 8 Abell Clusters: the dependence of tidally-induced star formation on cluster density

We have undertaken a survey of H alpha emission in a substantially complete sample of CGCG galaxies of types Sa and later within 1.5 Abell radii of the centres of 8 low-redshift Abell clusters. Some 320 galaxies were surveyed, of which 116 were detected in emission (39% of spirals, 75% of peculiars). Detected emission was classified as `compact' or `diffuse'. From an analysis of the full survey sample, we reconfirm our previous identification of compact and diffuse emission with circumnuclear starburst and disk emission respectively. The circumnuclear emission is associated either with the presence of a bar, or with a disturbed galaxy morphology indicative of on-going tidal interactions. The frequency of such tidally-induced (circumnuclear) starburst emission in spirals increases from regions of lower to higher local galaxy surface density, and from clusters with lower to higher central galaxy space density. We conclude that tidal interactions are likely to be the main mechanism for the transformation of spirals to S0s in clusters. Finally, for regions of comparable local density, the frequency of tidally-induced starburst emission is greater in clusters with higher central galaxy density. This implies that, for a given local density, morphological transformation of disk galaxies proceeds more rapidly in clusters of higher central galaxy density. This effect is considered to be due to subcluster merging and could account for the previously considered anomalous absence of a significant type - local surface density relation for irregular clusters at intermediate redshift.Comment: 22 pages including 4 figures. Accepted for publication in MNRA

Design considerations for a space database

Part of the information used in a real-time simulator is stored in the visual database. This information is processed by an image generator and displayed as a real-time visual image. The database must be constructed in a specific format, and it should efficiently utilize the capacities of the image generator that is was created for. A visual simulation is crucially dependent upon the success with which the database provides visual cues and recognizable scenes. For this reason, more and more attention is being paid to the art and science of creating effective real-time visual databases. Investigated here are the database design considerations required for a space-oriented real-time simulator. Space applications often require unique designs that correspond closely to the particular image-generator hardware and visual-database-management software. Specific examples from the databases constructed for NASA and its Evans and Sutherland CT6 image generator illustrate the various design strategies used in a space-simulation environment. These database design considerations are essential for all who would create a space database

Privileging information is inevitable

Libraries, archives and museums have long collected physical materials and other artefacts. In so doing they have established formal or informal policies defining what they will (and will not) collect. We argue that these activities by their very nature privilege some information over others and that the appraisal that underlies this privileging is itself socially constructed. We do not cast this in a post-modernist or negative light, but regard a clear understanding of it as fact and its consequences as crucial to understanding what collections are and what the implications are for the digital world. We will argue that in the digital world it is much easier for users to construct their own collections from a combination of resources, some privileged and curated by information professionals and some privileged by criteria that include the frequency with which other people link to and access them. We conclude that developing these ideas is an important part of placing the concept of a digital or hybrid paper/digital library on a firm foundation and that information professionals need to learn from each other, adopting elements of a variety of different approaches to describing and exposing information. A failure to do this will serve to push information professional towards the margins of the information seekers perspective

We are archivists, but are we OK?

Purpose – The purpose of this paper is to show that the digital environment of the early twenty-first century is forcing the information sciences to revisit practices and precepts built around paper and physical objects over centuries. The training of archivists, records managers, librarians and museum curators has had to accommodate this new reality. Often the response has been to superimpose a digital overlay on existing curricula. A few have taken a radical approach by scrutinising the fundamentals of the professions and the ontologies of the materials they handle. Design/methodology/approach – The article explores a wide range of the issues exposed by this critique through critical analysis of ideas and published literature. Findings – The authors challenge archive and records management educators to align their curricula with contemporary need and to recognise that partnership with other professionals, particularly in the area of technology, is essential. Practical implications – The present generation owe it to future generations of archivists and records managers to ensure that the education that they get to prepare them for professional life is forward-looking in the same way. Originality/value – This paper aims to raise awareness of the educational needs of twenty-first century archives and records professionals

The relationship between apamin binding and channel block in KCa2 potassium channels.

Small conductance calcium-activated potassium channels (KCa2.1,2.2,2.3) are widely distributed throughout the body and are involved in diverse physiological processes including the regulation of neuronal firing and smooth muscle contraction. They are also potential targets in the treatment of cardiac arrhythmia. The KCa2.2 and 2.3 members of the family are blocked by the peptide toxin apamin at low concentrations, however, the mechanism of block by apamin is unclear. In electrophysiological experiments apamin has been reported to block Kca2.2 and 2.3 with IC50 ~100 pM and ~1nM respectively. In contrast, in ligand binding experiments using [125I]-mono-iodoapamin it has been found that apamin does not discriminate between Kca2.2 and 2.3 and that it binds with significantly higher affinity ( ~5pM). This discrepancy has led to the suggestion that, rather than acting as a classical pore blocker, apamin exerts its action by an allosteric mechanism. It is notable that the ligand binding studies reported so far have been conducted with isolated cell membranes in non-physiological solution with low ionic strength. We have investigated this discrepancy between results from ligand binding and electrophysiological studies by comparing binding of [125I]-mono-iodoapamin and inhibition of KCa2 current in intact HEK 293 cells using identical physiological solutions. In these conditions we found that apamin bound to KCa2.1 and KCa 2.3 with KL 60 and 606 pM, close to values of IC50 from electrophysiological experiments. We also compared the ability of some known SK channel blockers, UCL 1848, UCL 1684, gallamine and dequalinium, to displace labelled apamin and inhibit KCa2 current. With these compounds we found a good correlation between K¬i and IC50. These findings suggest that the discrepancy between binding and block might arise from differences in the experimental protocols used. To examine this we examined apamin block of KCa2 current in low ionic strength solutions in which NaCl was iso-osmotically replaced by sucrose. In these conditions 100 pM apamin caused 92 ± 0.1 % block as against 51 ± 5 % block in physiological ionic strength. We conclude that binding data obtained from membrane preparations must be interpreted with care when making comparisons with data from functional experiments and that this has implications for current views on the mechanism of action of apamin as an SK channel blocke

General dissipation coefficient in low-temperature warm inflation

In generic particle physics models, the inflaton field is coupled to other bosonic and fermionic fields that acquire large masses during inflation and may decay into light degrees of freedom. This leads to dissipative effects that modify the inflationary dynamics and may generate a nearly-thermal radiation bath, such that inflation occurs in a warm rather than supercooled environment. In this work, we perform a numerical computation and obtain expressions for the associated dissipation coefficient in supersymmetric models, focusing on the regime where the radiation temperature is below the heavy mass threshold. The dissipation coefficient receives contributions from the decay of both on-shell and off-shell degrees of freedom, which are dominant for small and large couplings, respectively, taking into account the light field multiplicities. In particular, we find that the contribution from on-shell decays, although Boltzmann-suppressed, can be much larger than that of virtual modes, which is bounded by the validity of a perturbative analysis. This result opens up new possibilities for realizations of warm inflation in supersymmetric field theories.Comment: 25 pages, 13 figures; revised version with new results added; published in JCA

Curriculum Mapping: Bringing Evidence-Based Frameworks to Legal Education

This article explains the concept of curriculum mapping as used in the education profession and explains how it was applied in a mapping initiative at the NSU Law Center. Curriculum mapping is a process by which education professionals “document their own curriculum, then share and examine each other’s curriculums for gaps, overlaps, redundancies and new learning, creating a coherent, consistent, curriculum within and across areas that is ultimately aligned to standards and responsive to student data and other initiatives.” While this process has been used for many years in other areas of education, it is fairly new to legal education. This article explains the concepts, puts them into the context of other reforms currently happening in legal education, and through documenting our own experiences, gives a step-by-step primer on how to bring this useful tool to any law school to make evidence-based changes to a law school curriculum

Gaugino condensation in an improved heterotic M-theory

Gaugino condensation is discussed in the context of a consistent new version of low energy heterotic M-theory. The four dimensional reduction of the theory is described, based on simple boson and fermion backgrounds. This is generalised to include gaugino condenstates and various background fluxes, some with non-trivial topology. It is found that condensate and quantised flux contributions to the four-dimensional superpotential contain no corrections due to the warping of the higher dimensional metric.Comment: 11 pages, 4 figures, LaTe

Investigation in haemodynamic stability during intermittent haemodialysis in the critically ill

No abstract available