The final chapter of Elgin’s (True enough, The MIT Press, Cambridge,
2017
) defends the claim that some mistakes mark significant epistemic achievements. Here, I extend Elgin’s analysis of the ...informativeness of mistakes for epistemic policing. I also examine the type of theory of competence that Elgin’s view requires, and suggest some directions in which this can be taken.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Insects that inhabit high‐altitude ecosystems are an ecologically specialized group whose distribution is restricted by the presence of biogeographical barriers. These biogeographical constraints are ...thought to mould the shape of some insect structures because of environmental pressures that may produce better adaptations in extreme environments. We evaluated the potential distribution of Homocopris achamas and Uroxys coarctatus in two life regions (the Andean region and the Páramo region) found in the Andes of Colombia, and we determined if there were differences in their morphology along an elevational gradient. To determine the potential distribution of the species, we obtained geographical data through the systematic search of databases and entomological collections that we modelled under the maximum entropy model. We then evaluated the morphological variations by measuring geometric structures such as the clypeus (MC), the eye (ME) and the area of the anterior tibia (TA). We found that both species along the entire gradient exhibited the following characteristics: H. achamas was dominant in the Páramo region and showed two population nuclei separated by a wide biogeographic barrier, while U. coarctatus was more dominant in the Andean region and was distributed only in the northern Andes. Both were always linked to ecosystems with open vegetation that was both natural or intervened. H. achamas did not show changes in the shape of the structures while U. coarctatus showed differences in MC and ME. We suggested that livestock activity could act as an engine for breaking down biogeographical barriers allowing the distribution of a species to expand, and with this distributional expansion changes in the morphological structures of some species linked to their phenotypic plasticity could be promoted.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
3.
Imaging the Kramers-Henneberger atom Morales, Felipe; Richter, Maria; Patchkovskii, Serguei ...
Proceedings of the National Academy of Sciences - PNAS,
10/2011, Volume:
108, Issue:
41
Journal Article
Peer reviewed
Open access
Today laser pulses with electric fields comparable to or higher than the electrostatic forces binding valence electrons in atoms and molecules have become a routine tool with applications in laser ...acceleration of electrons and ions, generation of short wavelength emission from plasmas and clusters, laser fusion, etc. Intense fields are also naturally created during laser filamentation in the air or due to local field enhancements in the vicinity of metal nanoparticles. One would expect that very intense fields would always lead to fast ionization of atoms or molecules. However, recently observed acceleration of neutral atoms Eichmann et al. (2009) Nature 461: 1261-1264 at the rate of 10¹⁵ m/s² when exposed to very intense IR laser pulses demonstrated that substantial fraction of atoms remained stable during the pulse. Here we show that the electronic structure of these stable "laser-dressed" atoms can be directly imaged by photoelectron spectroscopy. Our findings open the way to visualizing and controlling bound electron dynamics in strong laser fields and reexamining its role in various strong-field processes, including microscopic description of high order Kerr nonlinearities and their role in laser filamentation Béjot et al. (2010) Phys Rev Lett 104:103903.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
In standard lasers, light amplification requires population inversion between an upper and a lower state to break the reciprocity between absorption and stimulated emission. However, in a medium ...prepared in a specific superposition state, quantum interference may fully suppress absorption while leaving stimulated emission intact, opening the possibility of lasing without inversion. Here we show that lasing without inversion arises naturally during propagation of intense femtosecond laser pulses in air. It is triggered by the combination of molecular ionization and molecular alignment, both unavoidable in intense light fields. The effect could enable inversionless amplification of broadband radiation in many molecular gases, opening unusual opportunities for remote sensing.
Quantum particles can penetrate potential barriers by tunnelling1. If that barrier is rotating, the tunnelling process is modified2,3. This is typical for electrons in atoms, molecules or solids ...exposed to strong circularly polarized laser pulses4–6. Here we measure how the transmission probability through a rotating tunnel depends on the sign of the magnetic quantum number m of the electron and thus on the initial direction of rotation of its quantum phase. We further show that our findings agree with a semiclassical picture, in which the electron keeps part of that rotary motion on its way through the tunnel by measuring m-dependent modification of the electron emission pattern. These findings are relevant for attosecond metrology as well as for interpretation of strong-field electron emission from atoms and molecules7–14 and directly demonstrate the creation of ring currents in bound states of ions with attosecond precision. In solids, this could open a way to inducing and controlling ring-current-related topological phenomena15.
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Stephen Grimm defends the idea that for understanding people, we need to think of understanding not only in terms of grasp of structure (be that causal or of other kinds) but also in terms of a ...notion of understanding-as-taking-to-be-good. In this paper, I critically examine this idea. First, I argue that in some cases, understanding-as-taking-to-be-good can be explained in terms of understanding-as-grasp-of-structure. Then, I consider one further way in which understanding-as-taking-to-be-good could be obtained through something which is not a form of grasp of structure, which narrows and refines Grimm's understanding-as-taking-to-be-good concept.
This study analyzes the impact of mobility, as a proxy for social distancing measures, on exports to the United States of America (USA). A mobility index based on Google mobility indicators was ...constructed using Principal Component Analysis (PCA), and an Accelerated Failure Time (AFT) model was fitted to the data on export survival from a group of Latin American countries (LATAM). Higher mobility levels are associated with an acceleration of the risk of interruption of exports. On average, LATAM shows higher export survival levels compared to other countries. Higher innovation and market concentration favored export survival, while higher levels of Real Effective Exchange Rate (REER) are associated with a lower probability of survival. Differences in survival were found between export sectors with regard to machinery and transportation equipment.
This article aims to connect issues in the epistemology of modality with issues in the philosophy of music, exploring how modalizing takes place in the context of musical performance. On the basis of ...studies of jazz improvisation and of classical music, it is shown that considerations about what is sonically, musically, and agentively possible play an important role for performers in the Western tonal tradition. We give a more systematic sketch of how a modal epistemology for musical performance could be constructed. We argue that it is necessary to adopt a pluralist approach toward the modal epistemology of music.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Tunnel ionization of noble gas atoms driven by a strong circularly polarized laser field in combination with a counter-rotating second harmonic generates spin-polarized electrons correlated to the ...spin-polarized ionic core. Crucially, such two-color field can bring the spin-polarized electrons back to the parent ion, enabling the scattering of the spin-polarized electron on the spin-polarized parent ion. Here we show how one can control the degree of spin polarization as a function of electron energy and recollision time by tuning the laser parameters, such as the relative intensities of the counter-rotating fields. The attosecond precision of the control over the degree of spin polarization opens the door for attosecond control and spectroscopy of spin-resolved dynamics.
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