Evaluating some computer enhancement algorithms that improve the visibility of cometary morphology

The observed morphology of cometary comae is determined by ejection circumstances and the interaction of the ejected material with the local environment. Anisotropic emission can provide useful information on such things as orientation of the nucleus, location of active areas on the nucleus, and the formation of ion structure near the nucleus. However, discrete coma features are usually diffuse, of low amplitude, and superimposed on a steep intensity gradient radial to the nucleus. To improve the visibility of these features, a variety of digital enhancement algorithms were employed with varying degrees of success. They usually produce some degree of spatial filtering, and are chosen to optimize visibility of certain detail. Since information in the image is altered, it is important to understand the effects of parameter selection and processing artifacts can have on subsequent interpretation. Using the criteria that the ideal algorithm must enhance low contrast features while not introducing misleading artifacts (or features that cannot be seen in the stretched, unprocessed image), the suitability of various algorithms that aid cometary studies were assessed. The strong and weak points of each are identified in the context of maintaining positional integrity of features at the expense of photometric information

Q^2-evolution of nucleon-to-resonance transition form factors in a QCD-inspired vector-meson-dominance model

We adopt the vector-meson-dominance approach to investigate Q^2-evolution of N-R transition form factors (N denotes nucleon and R an excited resonance) in the first and second resonance regions. The developed model is based upon conventional NR\gamma-interaction Lagrangians, introducing three form factors for spin-3/2 resonances and two form factors for spin-1/2 nucleon excitations. Lagrangian form factors are expressed as dispersionlike expansions with four or five poles corresponding to the lowest excitations of the mesons \rho(770) and \omega(782). Correct high-Q^2 form factor behavior predicted by perturbative QCD is due to phenomenological logarithmic renormalization of electromagnetic coupling constants and linear superconvergence relations between the parameters of the meson spectrum. The model is found to be in good agreement with all the experimental data on Q^2-dependence of the transitions N-\Delta(1232), N-N(1440), N-N(1520), N-N(1535). We present fit results and model predictions for high-energy experiments proposed by JLab. Besides, we make special emphasis on the transition to perturbative domain of N-\Delta(1232) form factors.Comment: 22 pages, 22 PS figures, REVTeX 4; v2: +3 refs, minor editorial change

Empirical Studies of Evolving Systems

This paper describes the results of the working group investigating the issues of empirical studies for evolving systems. The groups found that there were many issues that were central to successful evolution and this concluded that this is a very important area within software engineering. Finally nine main areas were selected for consideration. For each of these areas the central issues were identified as well as success factors. In some cases success stories were also described and the critical factors accounting for the success analysed. In some cases it was later found that a number of areas were so tightly coupled that it was important to discuss them together

Analysis of Recent Manifests for Goods Imported through US Ports

Several active interrogation techniques are being developed to detect shielded special nuclear materials (SNM) hidden in cargo containers loaded on container ships arriving at US ports. It raises the questions of the types of cargos in which SNM could be hidden, and their impact on detected signatures. Since the definition of a set of ''typical'' or standard cargos has proven to be difficult, we analyzed shipping manifests for US imports shipped through North American ports collected on 14 days distributed over 12 months. From these data, we generated several distribution functions such as commodity categories, average densities, and packaging types that could be of interest to the cargo scanning community. One of the cargo scanning techniques currently under development at LLNL is based on neutron active interrogation, and relies on the unique signature of beta-delayed gammas emitted by fission products in the 3 to 7 MeV energy range. {sup 19}F(n,a){sup 16}N, has been identified as the main potential interference for 7 and 9 MeV neutron beams. Estimates of cargo compositions based on manifests identified as containing fluorine are presented

Arctic and subarctic environmental analyses utilizing ERTS-1 imagery

The author has identified the following significant results. ERTS-1 imagery provides a means of distinguishing and monitoring estuarine surface water circulation patterns and changes in the relative sediment load of discharging rivers on a regional basis. Physical boundaries mapped from ERTS-1 imagery in combination with ground truth obtained from existing small scale maps and other sources resulted in improved and more detailed maps of permafrost terrain and vegetation for the same area. Snowpack cover within a research watershed has been analyzed and compared to ground data. Large river icings along the proposed Alaska pipeline route from Prudhoe Bay to the Brooks Range have been monitored. Sea ice deformation and drift northeast of Point Barrow, Alaska have been measured during a four day period in March and shore-fast ice accumulation and ablation along the west coast of Alaska have been mapped for the spring and early summer seasons

SAM Domain-Based Protein Oligomerization Observed by Live-Cell Fluorescence Fluctuation Spectroscopy

Sterile-alpha-motif (SAM) domains are common protein interaction motifs observed in organisms as diverse as yeast and human. They play a role in protein homo- and hetero-interactions in processes ranging from signal transduction to RNA binding. In addition, mutations in SAM domain and SAM-mediated oligomers have been linked to several diseases. To date, the observation of heterogeneous SAM-mediated oligomers in vivo has been elusive, which represents a common challenge in dissecting cellular biochemistry in live-cell systems. In this study, we report the oligomerization and binding stoichiometry of high-order, multi-component complexes of (SAM) domain proteins Ste11 and Ste50 in live yeast cells using fluorescence fluctuation methods. Fluorescence cross-correlation spectroscopy (FCCS) and 1-dimensional photon counting histogram (1dPCH) confirm the SAM-mediated interaction and oligomerization of Ste11 and Ste50. Two-dimensional PCH (2dPCH), with endogenously expressed proteins tagged with GFP or mCherry, uniquely indicates that Ste11 and Ste50 form a heterogeneous complex in the yeast cytosol comprised of a dimer of Ste11 and a monomer of Ste50. In addition, Ste50 also exists as a high order oligomer that does not interact with Ste11, and the size of this oligomer decreases in response to signals that activate the MAP kinase cascade. Surprisingly, a SAM domain mutant of Ste50 disrupted not only the Ste50 oligomers but also Ste11 dimerization. These results establish an in vivo model of Ste50 and Ste11 homo- and hetero-oligomerization and highlight the usefulness of 2dPCH for quantitative dissection of complex molecular interactions in genetic model organisms such as yeast

Influences on academics' approaches to development: voices from below

The purpose of this qualitative case study research was to explore faculty-based academics’ views on what influences their behaviours and attitudes towards their development. Informed by critical realist ontology, the data collection was carried out through narrative interviews with academics in two contrasting English Universities. Findings, or areas for reflection, have emerged about the constraints and enablements academics perceive in respect of their professional development. In particular, themes such as the significance of professional status; misaligned initiatives and priorities; the influence of supportive networks; and emergent personal, individual concerns have surfaced. The conclusion is drawn that the significance of agency raises the importance of responding to the ‘voices from below’

Valuing Arts-based Academic Projects in a Faculty of Nursing: Experiences of Graduate Students and Supervisors

Purpose: The purpose of this article is to explore student and supervisor experiences and perspectives regarding the advantages and challenges of arts-based projects in the context of graduate nursing education programs. We define arts-based academic projects as graduate level projects that incorporate a significant artistic component, and that culminate in a final written report of a capping exercise, a thesis or a dissertation. Procedures: Three graduate students were asked to briefly summarize their arts-based academic projects and to reflect upon their experiences with their projects, noting the advantages and challenges that they encountered in the process. The students’ supervisors also reported their experiences with supervising students conducting arts-based academic projects. The resulting written reflections were collated and summarized. Results: The arts-based academic projects included a set of comics, a story-based digital education tool and a digital knowledge whiteboard animation video. All of these projects integrated visual art into products for the purpose of knowledge translation. The students and their supervisors identified numerous advantages to arts-based projects, such as being able to address the complexities of context and to engage broad audiences. They reported challenges such as misunderstanding and devaluing the nature of these less traditional academic projects. Conclusions: This study has implications for future arts-based projects that may be conducted in Schools or Faculties of Nursing. Supervisors and committee members play a key role in fostering the creativity of students, building on their strengths, and encouraging them to pursue innovative theses or capping exercises. Similarly, graduate program coordinators/associate deans of graduate programs can also support these students by encouraging and approving projects that are less conventional and by helping others understand the value of these projects. Résumé Objectif : Cet article a pour but d’explorer les expériences et les perspectives d’étudiantes et de directrices de projets quant aux avantages et aux défis inhérents aux projets de nature artistique dans le cadre de programmes d’études supérieures en sciences infirmières. Nous définissons les projets d’études de nature artistique comme étant des travaux des cycles supérieurs qui comportent un important volet artistique et aboutissent à la rédaction d’un rapport de fin d’études, d’une thèse ou d’un mémoire. Approche : Nous avons demandé à trois étudiantes des cycles supérieurs de résumer leur projet artistique et de réfléchir sur leur expérience en soulignant les avantages et les défis rencontrés au court du processus. Les directrices de ces projets étudiants ont également décrit leur expérience de suivi de projets d’études de nature artistique. Nous avons colligé les réflexions écrites pour en faire la synthèse. Résultats : Les projets d’études de nature artistique qui ont été présentés comprenaient une bande dessinée comme moyen de diffusion de résultats de recherche, un outil numérique d’apprentissage basé sur un récit pour des parents et des enfants asthmatiques ,et une vidéo d’animation numérique de partage de connaissances sur tableau blanc pour les parents d’enfants qui ont gastroentérite aiguë. Tous ces projets intégraient les arts visuels dans des produits destinés au transfert de connaissances. Les étudiantes et les directrices de projets ont soulevé de nombreux avantages liés à de tels projets, comme la possibilité de rendre compte de la complexité du contexte et d’intéresser un large public. Les défis soulignés incluaient notamment l’incompréhension et la dévalorisation de tels projets d’études moins conventionnels. Conclusions : Cette synthèse peut avoir des répercussions sur d’éventuels projets d’études de nature artistique menés dans les écoles ou les facultés de sciences infirmières. Les directrices et les membres de comités jouent un rôle prépondérant auprès des étudiantes, soit de favoriser leur créativité, de développer leurs forces et de les encourager à envisager des thèses et des rapports de fin d’études avant-gardistes. De même, les responsables et les vice-doyennes des programmes de cycles supérieurs peuvent soutenir ces étudiantes en favorisant et en approuvant des travaux moins conventionnels, tout en aidant les autres à en comprendre la valeur