Search results for "53"
showing 10 items of 2908 documents
Computational methods and theory for ion channel research
2022
Ion channels are fundamental biological devices that act as gates in order to ensure selective ion transport across cellular membranes; their operation constitutes the molecular mechanism through which basic biological functions, such as nerve signal transmission and muscle contraction, are carried out. Here, we review recent results in the field of computational research on ion channels, covering theoretical advances, state-of-the-art simulation approaches, and frontline modeling techniques. We also report on few selected applications of continuum and atomistic methods to characterize the mechanisms of permeation, selectivity, and gating in biological and model channels.
ACKERMANS et al.
2019
One reason for the mammalian clade’s success is the evolutionary diversity of their teeth. In herbivores, this is represented by high‐crowned teeth evolved to compensate for wear caused by dietary abrasives like phytoliths and grit. Exactly how dietary abrasives wear teeth is still not understood completely. We fed four different pelleted diets of increasing abrasiveness (L: Lucerne; G: grass; GR: grass and rice husks; GRS: grass, rice husks, and sand) to four groups of a total of 28 adult goats, all with completely erupted third molars, over a six‐month period. Tooth morphology was captured by medical computed tomography scans at the beginning and end of the controlled feeding experi…
Gestión del cuerpo y planificación urbana: Desplazamiento de significado en la reivención de cuepos y ciudades
2020
Contemporary cities have administrations increasingly marked by urban planning guidelines that are guided by business and marketing and, to attract investments and tourists, implement strategies that aim to homogenize, spectacularize and control urban space. However, other experiences in the city potentially build new meaning to it, which would escape those strategically planned, creating alternative possibilities of uses, diverging from the way thar are predicted and proposed by the governmental power in their urban marketing strategies. The article discusses how the occupation of urban spaces by transvestites for prostitution may imply reflections on the role of norms of gender in the (re…
Probing the origin of ultra-high-energy cosmic rays with neutrinos in the EeV energy range using the Pierre Auger Observatory
2019
Neutrinos with energies above 1017 eV are detectable with the Surface Detector Array of the Pierre Auger Observatory. The identification is efficiently performed for neutrinos of all flavors interacting in the atmosphere at large zenith angles, as well as for Earth-skimming τ neutrinos with nearly tangential trajectories relative to the Earth. No neutrino candidates were found in ∼ 14.7 years of data taken up to 31 August 2018. This leads to restrictive upper bounds on their flux. The 90% C.L. single-flavor limit to the diffuse flux of ultra-high-energy neutrinos with an Eν -2 spectrum in the energy range 1.0 × 1017 eV -2.5 × 1019 eV is E2 dNν/dEν < 4.4 × 10-9 GeV cm-2 s-1 sr-1, placing str…
Imaging Spin Dynamics on the Nanoscale Using X-Ray Microscopy
2015
The dynamics of emergent magnetic quasiparticles, such as vortices, domain walls and bubbles are studied by scanning transmission X-ray microscopy (STXM), combining magnetic (XMCD) contrast with about 25 nm lateral resolution as well as 70 ps time resolution. Essential progress in the understanding of magnetic vortex dynamics is achieved by vortex core reversal observed by sub-GHz excitation of the vortex gyromode, either by ac magnetic fields or spin transfer torque. The basic switching scheme for this vortex core reversal is the generation of a vortex-antivortex pair. Much faster vortex core reversal is obtained by exciting azimuthal spin wave modes with (multi-GHz) rotating magnetic fiel…
Más allá de Marx: postobrerismo y posmarxismo. Una revisión de los fundamentos teóricos de la multitud y el pueblo
2018
The article is a synthetic essay that exposes the main theoretical lines of the postmarxist approach of Laclau and Mouffe, on the one hand, and the autonomist post-operaism of Negri, Hardt, Virno, etc., on the other hand. These theories are conceived as attempts to rationalize current political bets by various political sectors and social movements. It analyzes both argumentative strategies from «orthodox» Marxism and the structure / superstructure relationship; and the forms of constitution of new subjectivities. It compares the theoretical fundamentals of hegemonic articulations and counter-power experiences. It discusses, likewise, the scope and limitations of the categories of «people» …
Trabajo y TIC en los mayores de 45 años. Un análisis de la introducción al ciberespacio desde la esfera laboral
2018
The inequality in access to cyberspace due to age at the beginning of the twenty-first century was followed by an economic crisis that intensified many socio-labor dynamics. Through a contextualization with INE data and a qualitative sample, the following work tries to capture the attitudes about ICT related to their previous labor trajectories on those over 45 years of age; and, on the other hand, its introduction to cyberspace from work as a conditioner in the perception of crisis, the maintenance of employment or their way out to retirement.
Estimating QCD uncertainties in Monte Carlo event generators for gamma-ray dark matter searches
2018
Motivated by the recent galactic center gamma-ray excess identified in the Fermi-LAT data, we perform a detailed study of QCD fragmentation uncertainties in the modeling of the energy spectra of gamma-rays from Dark-Matter (DM) annihilation. When Dark-Matter particles annihilate to coloured final states, either directly or via decays such as $W^{(*)}\to q\bar{q}'$, photons are produced from a complex sequence of shower, hadronisation and hadron decays. In phenomenological studies, their energy spectra are typically computed using Monte Carlo event generators. These results have however intrinsic uncertainties due to the specific model used and the choice of model parameters, which are diffi…
Edges and Endpoints in 21-cm Observations from Resonant Photon Production
2020
Physical review letters 127(1), 011102 (1-7) (2021). doi:10.1103/PhysRevLett.127.011102
Computational Techniques for the Analysis of Small Signals in High-Statistics Neutrino Oscillation Experiments
2020
The current and upcoming generation of Very Large Volume Neutrino Telescopes – collecting unprecedented quantities of neutrino events – can be used to explore subtle effects in oscillation physics, such as (but not restricted to) the neutrino mass ordering. The sensitivity of an experiment to these effects can be estimated from Monte Carlo simulations. With the high number of events that will be collected, there is a trade-off between the computational expense of running such simulations and the inherent statistical uncertainty in the determined values. In such a scenario, it becomes impractical to produce and use adequately-sized sets of simulated events with traditional methods, such as M…