34 research outputs found
Dynamic zoom simulations: A fast, adaptive algorithm for simulating light-cones
No full textThe advent of a new generation of large-scale galaxy surveys is pushing cosmological numerical simulations in an uncharted territory. The simultaneous requirements of high resolution and very large volume pose serious technical challenges, due to their computational and data storage demand. In this paper, we present a novel approach dubbed dynamic zoom simulations – or dzs – developed to tackle these issues. Our method is tailored to the production of light-cone outputs from N-body numerical simulations, which allow for a more efficient storage and post-processing compared to standard comoving snapshots, and more directly mimic the format of survey data. In dzs, the resolution of the simulation is dynamically decreased outside the light-cone surface, reducing the computational work load, while simultaneously preserving the accuracy inside the light-cone and the large-scale gravitational field. We show that our approach can achieve virtually identical results to traditional simulations at half of the computational cost for our largest box. We also forecast this speedup to increase up to a factor of 5 for larger and/or higher resolution simulations. We assess the accuracy of the numerical integration by comparing pairs of identical simulations run with and without dzs. Deviations in the light-cone halo mass function, in the sky-projected light-cone, and in the 3D matter light-cone always remain below 0.1 per cent. In summary, our results indicate that the dzs technique may provide a highly valuable tool to address the technical challenges that will characterize the next generation of large-scale cosmological simulations
Accelerometrical and electromyo-graphical analysis of goalkeepers training with powerball
No full textThermal imaging as a tool of different breathing exercise characterization: a case study
No full textINTRODUCTION
Specific respiratory muscle training improves athletes’ performance particularly at high intensities (Esposito et al., 2010). The aim of this study was to evaluate two types of breathing, thoracic and diaphragmatic, used in respiratory training.
METHODS
An evaluation of different respiratory muscle training is possible by the use of IR thermography (AVIO, TVS-700), a non-invasive technique that visually represents the whole process during and after training (Merla et al., 2010). The subject performed the exercise with SpiroTiger® for 5 minutes, followed by a 5 minute recovery. The exercise was repeated 15 minutes after the end of recovery-time. Thoracic and diaphragmatic breathing exercises were performed using the same protocol in different days. Ten Regions of Interest (ROI) were selected following anatomical and functional correspondence with the muscles involved in breathing (Zaidi et al., 2007). The data were analyzed with specific thermal images software.
RESULTS
In order to check functional behaviour of respiratory muscles, we calculated the correlation coefficient (R) among thermal data of all the ROI and then grouped together ROI with strong correlation (R≥0.85). In thoracic exercises, correlated ROI were grouped into 4 areas corresponding to: pectoral muscles, rectus abdominus, intercostal muscles, abdominal oblique. In diaphragmatic exercises we found a strong correlation (R≥0.96) between thermal data of all the ROI. The temperature of the torso decreased by a few degrees during both trainings, but there was also an increase in pectoral muscles areas to be considered.
DISCUSSION
ROI of pectoral muscles in thoracic breathing are characterized by a linear heating during exercise and also a linear trend in the cooling-down process during the recovery time. The heating-up is linked to the work of the superficial muscles located in the upper part of the trunk that characterized the thoracic breathing. In diaphragmatic breathing, which mainly uses internal musculature, temperature does not increase in pectoral muscles areas. There is in fact a lesser contribution of superficial muscles used in thoracic breathing. In diaphragmatic breathing, more muscles synergistically participate to carry out an action: this is the reason for the strong correlation between the thermal data of all the areas.
REFERENCES
Esposito F., Limonta E., Alberti G., Veicsteinas A., Ferretti G. (2010). Respir. Physiol. Neurobiol. 170:268-272.
Merla, A., Mattei Peter A., Di Donato L., Romani G. (2010). Ann. Biomed. Eng. 38:158–163.
Zaidi H., Taiar R., Fohanno S., Polidori G. (2007). Acta Bioeng. Biomech. 9:47-51
Jndex operum. d. Johannis ignei doctoris aurelij moderni [et] regij Jnsubrium senatoris [et] primo eiusdem. Solemnis [et] valde quotidiana repeti. I. dudu[m]. L. de co[n]trahen. emptione. Eiusdem pomposa [et] elegantissima repetitio auctentice ex causa. L. de libe. prete. Jllustrissimo. d. Joan[n]i de Sane gallico cancellario dicata. ... Cum tabula in calce cuiuslibet earum positis preterq[ue] in auc. ex causa. in qua tabula com[m]odius in margine locanda fuit. ...
No full textRecommended from our members
Incipiu[n]t priuilegia ordinis fratrum heremitaru[m] sancti Augustini ::videl[icet] mare magnu[m] cu[m] i[n]nouatione ipsius : vna cu[m] quibusda[m] alijs priuilegijs & indultis ac supplicatio[n]ibus co[n]cessis [con]gregatio[n]i obseruantie Lombardie nuncupate eiusde[m] ordinis.
No full text
Quasars at the Cosmic Dawn: effects on Reionization properties in cosmological simulations
No full textAbstractWe study a model of cosmic reionization where quasars (QSOs) are the dominant source of ionizing photons at all relevant epochs. We employ a suite of adaptive hydrodynamical simulations post-processed with a multi-wavelength Monte Carlo radiative-transfer code and calibrate them in order to accurately reproduce the observed quasar luminosity function and emissivity evolution. Our results show that the QSO-only model fails in reproducing key observables linked to the Helium reionization, as the temperature evolution of the inter-galactic medium (IGM) and the HeII effective optical depth in synthetic Lyα spectra. Nevertheless, we find hints that an increased quasar contribution can explain recent measurements of a large inhomogeneity in the IGM at redshift z ≈ 5. Finally, we devise a method capable of constraining the QSOs contribution to the reionization from the properties of the HeII Lyα forest at z ≈ 3.5.</jats:p
Flows around galaxies. I. The dependency of galaxy connectivity on cosmic environments and effects on the star-formation rate
No full textWith the aim of bringing substantial insight to the fundamental question of
how galaxies acquire their material for star-formation, we present the first
comprehensive characterisation of the galaxy connectivity (i.e. the number of
small-scale filamentary streams connected to a galaxy) in relation with the
cosmic environment, and a statistical exploration of the impact of connectivity
on the star-formation rate at z=2. We detect kpc-scale filaments directly
connected to galaxies by applying the DisPerSE filament finder to the DM
density around 2942 central galaxies ( ) of
the TNG50-1 simulation. Our results demonstrate that galaxy connectivity spans
a broad range (from 0 to 9), with more than half of the galaxies connected to
two or three streams. We examine a variety of factors that could influence the
connectivity finding out that it increases with mass, decreases with local
density for low mass galaxies, and does not depend on local environment,
estimated by the Delaunay tessellation, for high mass galaxies. We further
classify galaxies according to their location in different cosmic web
environments, and we highlight the influence of the large-scale structure on
the number of connected streams. Our results reflect the different strengths of
the cosmic tides, which can prevent the formation of coherent streams feeding
the galaxies, or even disconnect the galaxy from its local web. Finally, we
show that, at fixed local density, the star-formation rate (SFR) of low mass
galaxies is up to enhanced due to connectivity. This SFR boost is
even more significant () for galaxies embedded in cosmic filaments,
where the available matter reservoirs are large. A milder impact is found for
high mass galaxies, hinting at different relative efficiencies of matter inflow
via small-scale streams in galaxies of different masses.Comment: published in A&
Evaluation of ERIC-PCR as Genotyping Method for Corynebacterium pseudotuberculosis Isolates.
No full textThe aim of this study was to evaluate the Enterobacterial Repetitive Intergenic Consensus (ERIC-PCR) as a tool for molecular typing of C. pseudotuberculosis isolates from eight different hosts in twelve countries. Ninety-nine C. pseudotuberculosis field strains, one type strain (ATCC 19410T ) and one vaccine strain (1002) were fingerprinted using the ERIC-1R and ERIC-2 primers, and the ERIC-1R+ERIC-2 primer pair. Twenty-nine different genotypes were generated by ERIC 1-PCR, 28 by ERIC 2-PCR and 35 by ERIC 1+2-PCR. The discriminatory index calculated for ERIC 1, ERIC 2, and ERIC 1+2-PCR was 0.89, 0.86, and 0.92, respectively. Epidemiological concordance was established for all ERIC-PCR assays. ERIC 1+2-PCR was defined as the best method based on suitability of the amplification patterns and discriminatory index. Minimal spanning tree for ERIC 1+2-PCR revealed three major clonal complexes and clustering around nitrate-positive (biovar Equi) and nitrate-negative (biovar Ovis) strains. Therefore, ERIC 1+2-PCR proved to be the best technique evaluated in this study for genotyping C. pseudotuberculosis strains, due to its usefulness for molecular epidemiology investigations
SPICE: the connection between cosmic reionisation and stellar feedback in the first galaxies
No full textWe present SPICE, a new suite of RHD cosmological simulations targeting the epoch of reionisation. The goal of these simulations is to systematically probe a variety of stellar feedback models, including bursty and smooth forms of supernova energy injection, as well as poorly-explored scenarios such as hypernova explosions and radiation pressure. Subtle differences in the behaviour of supernova feedback drive profound differences in reionisation histories, with burstier forms of feedback causing earlier reionisation. We also find that some global galaxy properties, such as the dust-attenuated luminosity functions and star formation main sequence, remain degenerate between models. Stellar feedback and its strength determine the morphological mix of galaxies emerging by z = 5 and that the reionisation history is inextricably connected to intrinsic properties such as galaxy kinematics and morphology. While star-forming, massive disks are prevalent if supernova feedback is smooth , bursty feedback preferentially generates dispersion-dominated systems. Different modes of feedback produce different strengths of outflows, altering the ISM/CGM in different ways, and in turn strongly affecting the escape of LyC photons. We establish a correlation between galaxy morphology and LyC escape fraction, revealing that dispersion-dominated systems have escape fractions 10-50 times higher than their rotation-dominated counterparts at all redshifts. Dispersion-dominated systems should thus preferentially generate large HII regions as compared to their rotation-dominated counterparts. Since dispersion-dominated systems are more prevalent if stellar feedback is more explosive, reionisation occurs earlier in our simulation with burstier feedback. Statistical samples of post-reionisation galaxy morphologies probed with JWST, ALMA and MUSE can constrain stellar feedback and models of cosmic reionisation.arXiv admin note: text overlap with arXiv:1801.07259 by other author
