Symmetric Skyrmions

We present candidates for the global minimum energy solitons of charge one to nine in the Skyrme model, generated using sophisticated numerical algorithms. Assuming the Skyrme model accurately represents the low energy limit of QCD, these configurations correspond to the classical nuclear ground states of the light elements. The solitons found are particularly symmetric, for example, the charge seven skyrmion has icosahedral symmetry, and the shapes are shown to fit a remarkable sequence defined by a geometric energy minimization (GEM) rule. We also calculate the energies and sizes to within at least a few percent accuracy. These calculations provide the basis for a future investigation of the low energy vibrational modes of skyrmions and hence the possibility of testing the Skyrme model against experiment.Comment: latex, 9 pages, 1 figure (fig1.gif

The effect of insulin on equine lamellar basal epithelial cells mediated by the insulin-like growth factor-1 receptor

Background In horses and ponies, insulin dysregulation leading to hyperinsulinemia may be associated with increased risk of laminitis, and prolonged infusion of insulin can induce the condition. It is unclear whether insulin may have a direct or indirect effect on the lamellar tissues. Insulin is structurally related to insulin-like growth factor (IGF-1), and can bind the IGF-1 receptor, albeit at a lower affinity than IGF-1. Methods Immunohistochemistry was performed on formalin-fixed lamellar tissue sections from six normal horses, euthanised for non-research purposes, using an anti-IGF-1 receptor antibody. In further studies, lamellar epithelial cells were obtained by collagenase digestion from the hooves of 18 normal horses, also euthanised for non-research purposes, and incubated for 48 h in the presence of insulin (0–2,000 m IU/ml). The increase in cell numbers was determined using a cell proliferation assay, and compared to the effect of zero insulin using one-way ANOVA. Results Immunohistochemistry demonstrated IGF-1 receptors on lamellar epidermal epithelial cells. With cultured cells, insulin caused a concentration-dependent increase in cell proliferation compared to untreated cells (maximal effect 63.3 ± 12.8% more cells after 48 h with 1,000 m IU/ml insulin; P < 0.01). Co-incubation with a blocking antibody against the IGF-1 receptor significantly inhibited the proliferative effect of insulin (P < 0.01). Discussion These results demonstrate that IGF-1 receptors are present on lamellar epithelial cells. At high physiological concentrations, insulin may activate these cells, by a mechanism involving IGF-1 receptors, resulting in a proliferative effect. This mechanism could help to explain the link between hyperinsulinemia and laminitis

Zero mode quantization of multi-Skyrmions

A zero mode quantization of the minimal energy SU(2) Skyrmions for nucleon numbers four to nine and seventeen is described. This involves quantizing the rotational and isorotational modes of the configurations. For nucleon numbers four, six and eight the ground states obtained are in agreement with the observed nuclear states of Helium, Lithium and Beryllium. However, for nucleon numbers five, seven, nine and seventeen the spins obtained conflict with the observed isodoublet nuclear states.Comment: 37 pages, LaTeX, 4 figures. More careful treatment of double covers, reference adde

Innovation accelerator to make portuguese parishes smarter

Vizela, I., Costa, E., & Santos, V. (2020). Innovation accelerator to make portuguese parishes smarter. In M. Banat, & S. Paiva (Eds.), Smart Technologies for Smart Cities: EAI/Springer Innovations in Communication and Computing (pp. 3-21). (EAI/Springer Innovations in Communication and Computing). Springer. https://doi.org/10.1007/978-3-030-39986-3_1The main motivation behind this study was the need to get citizens and parish councils closer. For this purpose, an innovation accelerator to bring smartness to parishes was built. To get all insight, there was the need to learn more about public administration and smart cities and a bit more on innovation and creativity. During the research process, it was also understood that smartness inside a parish must include an improvement on the relationship with citizens, citizens who feel that their opinions count, and citizens’ training to promote digital inclusion and also for parish employees to make sure that their processes are more citizen-centered and an improvement of citizens’ quality of living inside the parish. Those issues were addressed in the final model. The obtained model was validated by a focus group, and it was concluded that the implementation of the proposed framework in a Portuguese parish is aligned with what parishes want for them in the near future.authorsversionpublishe

The role of the supply chain in the elimination and reduction of construction rework and defects: an action research approach

Since 2007, Ireland has suffered a circa 80% reduction in construction output. This has resulted in bankruptcy, unemployment and bad debt. Contractors have attached greater emphasis to production efficiency and cost reduction as a means of survival. An Action Research (AR) strategy was used in this research to improve processes adopted by a SME contractor for the control of defects in its supply chain. It is conservatively estimated that rework, typically accounts for, circa 5% of total project costs. Rework is wasteful and presents an obvious target for improvement. The research reported here concerns the (first) diagnosing stage of the AR cycle only, involving: observation of fieldwork, analysis of contract documents, and semi-structured interviews with supply chain members. The results indicate potential for supply chain participants to identify root causes of defects and propose solutions, having regard to best practice to avoid re-occurrence. A lack of collaborative forums to contribute to production improvement was identified. Additionally the processes, used to collect, manage and disseminate data were unstructured and uncoordinated, indicating scope for developing more efficient methods. The research indicates good understanding of the potential benefits for supply chain collaboration but suggests that the tools and knowledge to collaborate are currently lacking in the SME sector

Spatial Guilds in the Serengeti Food Web Revealed by a Bayesian Group Model

Food webs, networks of feeding relationships among organisms, provide fundamental insights into mechanisms that determine ecosystem stability and persistence. Despite long-standing interest in the compartmental structure of food webs, past network analyses of food webs have been constrained by a standard definition of compartments, or modules, that requires many links within compartments and few links between them. Empirical analyses have been further limited by low-resolution data for primary producers. In this paper, we present a Bayesian computational method for identifying group structure in food webs using a flexible definition of a group that can describe both functional roles and standard compartments. The Serengeti ecosystem provides an opportunity to examine structure in a newly compiled food web that includes species-level resolution among plants, allowing us to address whether groups in the food web correspond to tightly-connected compartments or functional groups, and whether network structure reflects spatial or trophic organization, or a combination of the two. We have compiled the major mammalian and plant components of the Serengeti food web from published literature, and we infer its group structure using our method. We find that network structure corresponds to spatially distinct plant groups coupled at higher trophic levels by groups of herbivores, which are in turn coupled by carnivore groups. Thus the group structure of the Serengeti web represents a mixture of trophic guild structure and spatial patterns, in contrast to the standard compartments typically identified in ecological networks. From data consisting only of nodes and links, the group structure that emerges supports recent ideas on spatial coupling and energy channels in ecosystems that have been proposed as important for persistence.Comment: 28 pages, 6 figures (+ 3 supporting), 2 tables (+ 4 supporting

Features of mammalian microRNA promoters emerge from polymerase II chromatin immunoprecipitation data

Background: MicroRNAs (miRNAs) are short, non-coding RNA regulators of protein coding genes. miRNAs play a very important role in diverse biological processes and various diseases. Many algorithms are able to predict miRNA genes and their targets, but their transcription regulation is still under investigation. It is generally believed that intragenic miRNAs (located in introns or exons of protein coding genes) are co-transcribed with their host genes and most intergenic miRNAs transcribed from their own RNA polymerase II (Pol II) promoter. However, the length of the primary transcripts and promoter organization is currently unknown. Methodology: We performed Pol II chromatin immunoprecipitation (ChIP)-chip using a custom array surrounding regions of known miRNA genes. To identify the true core transcription start sites of the miRNA genes we developed a new tool (CPPP). We showed that miRNA genes can be transcribed from promoters located several kilobases away and that their promoters share the same general features as those of protein coding genes. Finally, we found evidence that as many as 26% of the intragenic miRNAs may be transcribed from their own unique promoters. Conclusion: miRNA promoters have similar features to those of protein coding genes, but miRNA transcript organization is more complex. © 2009 Corcoran et al

Vesicular stomatitis virus enables gene transfer and transsynaptic tracing in a wide range of organisms

Current limitations in technology have prevented an extensive analysis of the connections among neurons, particularly within nonmammalian organisms. We developed a transsynaptic viral tracer originally for use in mice, and then tested its utility in a broader range of organisms. By engineering the vesicular stomatitis virus (VSV) to encode a fluorophore and either the rabies virus glycoprotein (RABV-G) or its own glycoprotein (VSV-G), we created viruses that can transsynaptically label neuronal circuits in either the retrograde or anterograde direction, respectively. The vectors were investigated for their utility as polysynaptic tracers of chicken and zebrafish visual pathways. They showed patterns of connectivity consistent with previously characterized visual system connections, and revealed several potentially novel connections. Further, these vectors were shown to infect neurons in several other vertebrates, including Old and New World monkeys, seahorses, axolotls, and Xenopus. They were also shown to infect two invertebrates, Drosophila melanogaster, and the box jellyfish, Tripedalia cystophora, a species previously intractable for gene transfer, although no clear evidence of transsynaptic spread was observed in these species. These vectors provide a starting point for transsynaptic tracing in most vertebrates, and are also excellent candidates for gene transfer in organisms that have been refractory to other methods

Can forest management based on natural disturbances maintain ecological resilience?

Given the increasingly global stresses on forests, many ecologists argue that managers must maintain ecological resilience: the capacity of ecosystems to absorb disturbances without undergoing fundamental change. In this review we ask: Can the emerging paradigm of natural-disturbance-based management (NDBM) maintain ecological resilience in managed forests? Applying resilience theory requires careful articulation of the ecosystem state under consideration, the disturbances and stresses that affect the persistence of possible alternative states, and the spatial and temporal scales of management relevance. Implementing NDBM while maintaining resilience means recognizing that (i) biodiversity is important for long-term ecosystem persistence, (ii) natural disturbances play a critical role as a generator of structural and compositional heterogeneity at multiple scales, and (iii) traditional management tends to produce forests more homogeneous than those disturbed naturally and increases the likelihood of unexpected catastrophic change by constraining variation of key environmental processes. NDBM may maintain resilience if silvicultural strategies retain the structures and processes that perpetuate desired states while reducing those that enhance resilience of undesirable states. Such strategies require an understanding of harvesting impacts on slow ecosystem processes, such as seed-bank or nutrient dynamics, which in the long term can lead to ecological surprises by altering the forest's capacity to reorganize after disturbance