The impact of metallicity and dynamics on the evolution of young star clusters

The early evolution of a dense young star cluster (YSC) depends on the intricate connection between stellar evolution and dynamical processes. Thus, N-body simulations of YSCs must account for both aspects. We discuss N-body simulations of YSCs with three different metallicities (Z=0.01, 0.1 and 1 Zsun), including metallicity-dependent stellar evolution recipes and metallicity-dependent prescriptions for stellar winds and remnant formation. We show that mass-loss by stellar winds influences the reversal of core collapse. In particular, the post-collapse expansion of the core is faster in metal-rich YSCs than in metal-poor YSCs, because the former lose more mass (through stellar winds) than the latter. As a consequence, the half-mass radius expands more in metal-poor YSCs. We also discuss how these findings depend on the total mass and on the virial radius of the YSC. These results give us a clue to understand the early evolution of YSCs with different metallicity.Comment: to appear in "Massive Young Star Clusters Near and Far: From the Milky Way to Reionization", 2013 Guillermo Haro Conference, Eds. Y. D. Mayya, D. Rosa-Gonzalez & E. Terlevich, INAOE and AMC. 4 pages, 2 figure

Forming circumnuclear disks and rings in galactic nuclei: a competition between supermassive black hole and nuclear star cluster

We investigate the formation of circumnuclear gas structures from the tidal disruption of molecular clouds in galactic nuclei, by means of smoothed particle hydrodynamics simulations. We model galactic nuclei as composed of a supermassive black hole (SMBH) and a nuclear star cluster (NSC) and consider different mass ratios between the two components. We find that the relative masses of the SMBH and the NSC have a deep impact on the morphology of the circumnuclear gas. Extended disks form only inside the sphere of influence of the SMBH. In contrast, compact rings naturally form outside the SMBH's sphere of influence, where the gravity is dominated by the NSC. This result is in agreement with the properties of the Milky Way's circumnuclear ring, which orbits outside the SMBH sphere of influence. Our results indicate that compact circumnuclear rings can naturally form outside the SMBH sphere of influence.Comment: Accepted for publication in ApJ. 12 pages, 6 figures, 3 tables. Comments welcom

Runway exit designs for capacity improvement demonstrations. Phase 2: Computer model development

The development is described of a computer simulation/optimization model to: (1) estimate the optimal locations of existing and proposed runway turnoffs; and (2) estimate the geometric design requirements associated with newly developed high speed turnoffs. The model described, named REDIM 2.0, represents a stand alone application to be used by airport planners, designers, and researchers alike to estimate optimal turnoff locations. The main procedures are described in detail which are implemented in the software package and possible applications are illustrated when using 6 major runway scenarios. The main output of the computer program is the estimation of the weighted average runway occupancy time for a user defined aircraft population. Also, the location and geometric characteristics of each turnoff are provided to the user

Runway Exit Designs for Capacity Improvement Demonstrations. Phase 1: Algorithm Development

A description and results are presented of a study to locate and design rapid runway exits under realistic airport conditions. The study developed a PC-based computer simulation-optimization program called REDIM (runway exit design interactive model) to help future airport designers and planners to locate optimal exits under various airport conditions. The model addresses three sets of problems typically arising during runway exit design evaluations. These are the evaluations of existing runway configurations, addition of new rapid runway turnoffs, and the design of new runway facilities. The model is highly interactive and allows a quick estimation of the expected value of runway occupancy time. Aircraft populations and airport environmental conditions are among the multiple inputs to the model to execute a viable runway location and geometric design solution. The results presented suggest that possible reductions on runway occupancy time (ROT) can be achieved with the use of optimally tailored rapid runway designs for a given aircraft population. Reductions of up to 9 to 6 seconds are possible with the implementation of 30 m/sec variable geometry exits

On the Theory of Evolution Versus the Concept of Evolution: Three Observations

Here we address three misconceptions stated by Rice et al. in their observations of our article Paz-y-Miño and Espinosa (Evo Edu Outreach 2:655–675, 2009), published in this journal. The five authors titled their note “The Theory of Evolution is Not an Explanation for the Origin of Life.” First, we argue that it is fallacious to believe that because the formulation of the theory of evolution, as conceived in the 1800s, did not include an explanation for the origin of life, nor of the universe, the concept of evolution would not allow us to hypothesize the possible beginnings of life and its connections to the cosmos. Not only Stanley Miller’s experiments of 1953 led scientists to envision a continuum from the inorganic world to the origin and diversification of life, but also Darwin’s own writings of 1871. Second, to dismiss the notion of Rice et al. that evolution does not provide explanations concerning the universe or the cosmos, we identify compelling scientific discussions on the topics: Zaikowski et al. (Evo Edu Outreach 1:65–73, 2008), Krauss (Evo Edu Outreach 3:193–197, 2010), Peretó et al. (Orig Life Evol Biosph 39:395–406, 2009) and Follmann and Brownson (Naturwissenschaften 96:1265–1292, 2009). Third, although we acknowledge that the term Darwinism may not be inclusive of all new discoveries in evolution, and also that creationists and Intelligent Designers hijack the term to portray evolution as ideology, we demonstrate that there is no statistical evidence suggesting that the word Darwinism interferes with public acceptance of evolution, nor does the inclusion of the origin of life or the universe within the concept of evolution. We examine the epistemological and empirical distinction between the theory of evolution and the concept of evolution and conclude that, although the distinction is important, it should not compromise scientific logic

Symbolic-Numeric Algorithms for Computer Analysis of Spheroidal Quantum Dot Models

A computation scheme for solving elliptic boundary value problems with axially symmetric confining potentials using different sets of one-parameter basis functions is presented. The efficiency of the proposed symbolic-numerical algorithms implemented in Maple is shown by examples of spheroidal quantum dot models, for which energy spectra and eigenfunctions versus the spheroid aspect ratio were calculated within the conventional effective mass approximation. Critical values of the aspect ratio, at which the discrete spectrum of models with finite-wall potentials is transformed into a continuous one in strong dimensional quantization regime, were revealed using the exact and adiabatic classifications.Comment: 6 figures, Submitted to Proc. of The 12th International Workshop on Computer Algebra in Scientific Computing (CASC 2010) Tsakhkadzor, Armenia, September 5 - 12, 201

Pandemic influenza A/H1N1 virus in a swine farm house in Sicily, Italy

This report describes a pandemic A/H1N1 (H1N1 pdm) virus outbreak occurred in December, 2009 in a swine farm used as research facility (Istituto Mediterraneo Trapianti e Terapie ad Alta Specializzazione) for preclinical studies, located in Sicily, Italy. All the 13 pigs of the farm, showed cough, fever, inappetence and weakness. At the same time, an unvaccinated worker of the stabling showed influenza-like symptoms. RNAv extracted from two swabs collected from infected pigs resulted positive by Real Time RT-PCR for Influenza A virus. Furthermore, after growth on embryonated eggs, viral isolates were identified by Real Time RT-PCR specific for H1N1 pdm virus and characterized antigenically. Sequencing of the whole genome was also performed. All sera taken from animals and from the worker were tested by a competitive Influenza A ELISA and by the haemoagglutination inhibition test. Serological findings confirmed the circulation of influenza virus H1N1 pdm in pigs and the presence of specific antibodies against H1N1 pdm in human serum. The results of this study seem to support a H1N1 pdm transmission from man to animals showing the importance of serological and virological investigation to control the pig farms and the importance of close cooperation between the different authorities like veterinarian and human public. © 2012 Triveni Enterprises

Adiabatic description of nonspherical quantum dot models

Within the effective mass approximation an adiabatic description of spheroidal and dumbbell quantum dot models in the regime of strong dimensional quantization is presented using the expansion of the wave function in appropriate sets of single-parameter basis functions. The comparison is given and the peculiarities are considered for spectral and optical characteristics of the models with axially symmetric confining potentials depending on their geometric size making use of the total sets of exact and adiabatic quantum numbers in appropriate analytic approximations

Image segmentation applied to urban surface and aerial constraints analysis

The rapid progress of artificial intelligence (AI) has prompted the exploration of its potential applications in the construction industry, although at a slower rate. Since the starting point of a design is the analysis of the site’s constraints, the purpose of the ongoing research is the application of artificial intelligence in risk assessment for site areas. The primary objective of this research project is to develop an interactive map that employs AI to identify potential surface and aerial interferences. This map aims to support planners, engineers, and architects during the site context analysis phase by providing real-time visualization of obstacles. The interactive map allows users to explore and analyze identified obstacles, enabling cluster markers and filtering of features. The results obtained from applying this approach in Milan, Italy, demonstrate its functionality and usability, highlighting the tool's ability to provide valuable information in both localized and citywide scenarios. Potential improvements such as size assessment and advanced marker generation are also being examined to enhance the management of surface and air interferences. The goal is to enhance the tool's functionality, accuracy, and planning efficiency in construction projects

New horizons for a worker-effective training method in the AEC Sector

The training of site professionals is typically perceived as being monotonous, and ineffective in terms of information assimilation and retention. Furthermore, traditional training approaches such as lecture-based presentations, have been demonstrated to be unsuccessful at engaging site workers, resulting in decreased attention and motivation. This paper aims to develop the framework for gamified training, of site workers. It is intended to value the requirements that European H&S standards expect to be kept under surveillance. The outcome of this work is the definition of a new reward procedure focused on ongoing improvement via feedback to low-scoring individuals. Multiple screen boards are designed to facilitate key context interaction and possible reactions. This study outlines two theoretical applications of training, the first applicable transversally to many situations (i.e. Educational Construction Site Information Modeling) and the second as a site-specific solution based on its digital twin (i.e. Mockup Construction Site Information Modeling) intended to accurately foresee and train workers for dangerous operations