Pattern Formation with a Compartmental Lateral Inhibition System

We propose a compartmental lateral inhibition system that generates contrasting patterns of gene expression between neighboring compartments. The system consists of a set of compartments interconnected by channels. Each compartment contains a colony of cells that produce diffusible molecules to be detected by the neighboring colony, and each cell is equipped with an inhibitory circuit that reduces its production when the detected signal is stronger. We develop a technique to analyze the steady-state patterns emerging from this lateral inhibition system and apply it to a specific implementation. The analysis shows that the proposed system indeed exhibits contrasting patterns within realistic parameter ranges.Comment: 9 pages, 6 figure

Sphere-sphere intersection for investment portfolio diversification - A new data-driven cluster analysis.

Aiming at supporting the process of investment portfolio diversification by using a data-driven approach, the present methodological paper proposes a new cluster analysis, which compares publicly traded companies, mainly in times of high volatility (e.g. crisis times). The main goal of the proposed method is to provide a less arbitrary analysis to support financial investors to precisely measure the degree of similarity between equity stocks, unveiling equity market clustering patterns by applying analytic geometry solutions and calculating an overall clustering pattern indicator. Empirical results on synthetic data demonstrate either that the proposed method has conceptual superiority over traditional cluster analyses and its potential practical usefulness to asset allocation, portfolio strategy, asset pricing, among other related purposes. Finally, the outputs of the proposed cluster analysis are presented through an intuitive and easily understandable mathematical visualization. •It is proposed a new method to calculate risk-similarity and clustering patterns.•The method unveils clustering patterns through a data-driven process.•Portfolio diversification can benefit from sphere-sphere intersection calculations

Crenicichla tigrina, une nouvelle espèce de Ciclidae (Pisces, Perciformes) du Rio Trombetas, Para, Brésil

Une nouvelle espèce de Cichlidae, #Crenicichla tigrina, est décrite et illustrée. La coloration sur le vivant et quelques remarques relatives à l'écologie de cette espèce sont présentées. Les relations de #C. tigrina avec les autres espèces de #Crenicichla à petites écailles et le mode de distribution de ces espèces sont discutés. Le biotope de #C. tigrina est défini par l'étude de la faune associée. Le mode de distribution est comparé avec celui d'autres taxa chez les poissons. (Résumé d'auteur

Real estate data to analyse the relationship between property prices, sustainability levels and socio-economic indicators.

Recent studies have sought to explore the relationship between environmental and financial performance, in particular the relationship between the energy efficiency level of a building and its financial value. The present real estate dataset contains 43 variables of repeat sales transactions, energy performance certificate (EPC) rating, index of multiple deprivation (IMD), and geographical location of properties in England and Wales involved in a total of 4,201 transactions from 1995 to 2012. This dataset enables researchers and practitioners to further explore important questions regarding the nexus between the real estate industry, sustainability levels, and socio-economic aspects. Due to the scarcity of publicly available quality real estate data, the dataset detailed in this article may play a relevant role by becoming easily discoverable, clearly explained, and structured to be ready to be used by researchers, analysts, and policymakers. The empirical analysis of the economic case for energy-efficient dwellings in the UK private rental market performed in Fuerst, et al. [1] is based on this dataset

Une nouvelle espèce de Bryconexodon (Pisces, Characidae) décrite du bassin du Trombetas (Para, Brésil)

Une nouvelle espèce du genre #Bryconexodon Géry (#Pisces, #Characidae) est décrite du cours supérieur du Rio Trombetas (Para, Brésil). #Bryconexodon n. sp. est très voisine de #B. juruenae Guéry, 1980 par la forme et la distribution des dents, mais présente moins d'écailles en ligne latérale (13-15 contre 17-19), moins de séries d'écailles au-dessus de la ligne latérale (8-9 contre 10-12) et autour du pédoncule caudale (16-18 contre 22). L'examen de contenus stomacaux révèle que #B. trombetasi n. sp. est lépidophage. (Résumé d'auteur

Une nouvelle espèce du genre Mylesinus (Pisces, Serrasalmidae), M. paraschomburgkii, décrite des bassins du Trombetas et du Uatuma (Brésil, Amazonie)

Une série de collectes, réalisées dans le bassin du Trombetas (Brésil, Para) et le bassin du Uatuma (Brésil, Amazonas), a permis de récolter de nombreux spécimens du genre #Mylesinus (Characiformes, #Serrasalmidae) de 13 à 365 mm de longueur standard. Après une mise au point de la littérature se rapportant au genre #Mylesinus, M. paraschomburgkii$ n.sp. est décrite. Au cours de la croissance, cette espèce présente de nombreuses modifications morphologiques et anatomiques. Certains caractères, comme la hauteur du corps ou la longueur de la tête, présentent de fortes allométries de croissance qui s'atténuent au-delà de 80 mm de longueur standard. Le nombre de dents à la mâchoire inférieure augmente régulièrement avec la taille des spécimens et, parallèlement, les dents, caniniformes et pointues chez les jeunes, deviennent plus larges et incisiformes. L'intestin présente une forte allométrie positive et son mode d'enroulement se modifie au cours de la croissance. Les auteurs relient ces modifications anatomiques à celle du régime alimentaire qui passe de carnivore à phytophage brouteur à partir de 50 mm de longueur standard. (Résumé d'auteur

What Drives Households to Buy Flood Insurance? Evidence from Georgia

Benefiting from access to detailed data on the federally run National Flood Insurance Program for the entire state of Georgia, USA, we analyze residential flood insurance purchasing behavior in that state over more than three decades (1978–2010). The demand for flood insurance on an extensive margin, based on take-up rates, is found to be relatively price inelastic. Aligned with the behavioral economics literature, recent flood events temporarily increase purchases, but this effect fades after 3 years. We also find that the proportion of developed area in floodplains has a significant positive impact on insurance take-up rates. Contrary to what is often assumed, we do not find evidence that insurance purchase and mitigation efforts are substitutes. Educated individuals, individuals over the age of 45, and African-Americans are, all else equal, more likely to purchase flood insurance

TOFtracker: combination of time-of-flight and high-accuracy bidimensional tracking in a single gaseous detector

A 5-gap timing RPC equipped with patterned electrodes coupled to both charge-sensitive and timing circuits yields a time accuracy of 77 ps along with a position accuracy of 38 μm. These results were obtained by calculating the straight-line fit residuals to the positions provided by a 3-layer telescope made out of identical detectors, detecting almost perpendicular cosmic-ray muons. The device may be useful for particle identification by time-of-flight, where simultaneous measurements of trajectory and time are necessary

The resonance amplitude associated with the Gamow states

The Gamow states describe the quasinormal modes of quantum systems. It is shown that the resonance amplitude associated with the Gamow states is given by the complex delta function. It is also shown that under the near-resonance approximation of neglecting the lower bound of the energy, such resonance amplitude becomes the Breit-Wigner amplitude. This result establishes the precise connection between the Gamow states, Nakanishi's complex delta function and the Breit-Wigner amplitude. In addition, this result provides another theoretical basis for the phenomenological fact that the almost-Lorentzian peaks in cross sections are produced by intermediate, unstable particles

Surface drift prediction in the Adriatic Sea using hyper-ensemble statistics on atmospheric, ocean and wave models : uncertainties and probability distribution areas

Author Posting. © NATO Undersea Research Centre, 2007. This article is posted here by permission of NATO Undersea Research Centre for personal use, not for redistribution. The definitive version was published in Journal of Marine Systems 69 (2008): 86-98, doi:10.1016/j.jmarsys.2007.02.015.Despite numerous and regular improvements in underlying models, surface drift prediction in the ocean remains a challenging task because of our yet limited understanding of all processes involved. Hence, deterministic approaches to the problem are often limited by empirical assumptions on underlying physics. Multi-model hyper-ensemble forecasts, which exploit the power of an optimal local combination of available information including ocean, atmospheric and wave models, may show superior forecasting skills when compared to individual models because they allow for local correction and/or bias removal. In this work, we explore in greater detail the potential and limitations of the hyper-ensemble method in the Adriatic Sea, using a comprehensive surface drifter database. The performance of the hyper-ensembles and the individual models are discussed by analyzing associated uncertainties and probability distribution maps. Results suggest that the stochastic method may reduce position errors significantly for 12 to 72 h forecasts and hence compete with pure deterministic approaches.Funded by the North Atlantic Treaty Organization