Cartographier l’ontologie d’un territoire sur le web: Le cas de la Bolivie

International audienceUnder what conditions is it possible to define the identity of a territory on the Web? In this paper we explore the way entities with a clear-cut geographical existence (such as Bolivia) exist and are objectivized in a digital space like the Web. Our question is “should the mapping of a territorial entity on the Web and its traditional geographical representation converge?” In order to answer it, we set out an analysis which takes as its starting point the architecture of the Web, revolving around the notion of resource (objects identified on the Web). Therefrom, we conduct an anthropological analysis of the “modes of existence” (Etienne Souriau) of a country such as Bolivia on the Web. We use several digital methods in order to probe concrete examples of the networks of associations it elicits and show that, as a resource, its limits that are widely redefined on the Web, largely through the networks generated by online participation (blogs, commentaries, tweets, Wikipedia entries…). Bolivia can thence be described as a burgeoning, quite unstable, entity whose borders become rather imprecise. Yet, such a characterization also proves way more encompassing and richer than traditional (namely, geographic) ones.Quelle est l’identité d’un territoire sur le Web ? Dans cet article nous explorons les modes d’identification et d’objectivation d’entités (en l’occurrence, ici, un pays) ayant une existence géographique admise hors du Web. Il apparait que la Bolivie, en tant qu’objet identifié au moyen du Web, alimenté par des contenus participatifs (blogs, commentaires, tweets, articles Wikipédia, contenus structurées sur DBpedia, etc.), est une entité en devenir qui prolifère et non un référent stable aux bords nets. Grâce à cette hypothèse permettant de penser sérieusement l’existence à part entière d’une entité sur le Web, nous pouvons mener une enquête anthropologique à propos de ces deux modes d’existence (au sens d’Etienne Souriau) de l’entité Bolivie. La cartographie d’une entité territoriale sur le Web et sa cartographie géographique se recouvrent-elles ? Et selon quelles dimensions le cas échéant ? Nous verrons que la question à se poser sur le Web est avant tout une question d’échelles. Pour ce faire, nous repartirons des fondements de l’architecture du Web afin de déterminer comment faire varier les échelles sur le Web de manière à continuer à parler de la Bolivie (une entité une) tout en tenant compte de la prolifération des associations qu’elle tisse (une entité multiple) et ainsi enrichir notre appréhension de l’objet géographique Bolivie "hors" du Web (objet dont l’existence est néanmoins impactée par le Web selon des modalités à éclaircir)

Les réalités du monde microbien chez les éleveurs de petits ruminants : enquêtes anthropologiques partant de l’exemple de la fièvre Q

National audienceLes réalités du monde microbien chez les éleveurs de petits ruminants : enquêtes anthropologiques partant de l'exemple de la fièvre Q Journées scientifiques AEEMA 13 mai 202

Les réalités du monde microbien chez les éleveurs de petits ruminants : enquêtes anthropologiques partant de l’exemple de la fièvre Q

National audienceLes réalités du monde microbien chez les éleveurs de petits ruminants : enquêtes anthropologiques partant de l'exemple de la fièvre Q Journées scientifiques AEEMA 13 mai 202

Fièvre Q : état d'avancement du projet EXPAIRCOX sur les risques de transmission et la perception de ces risques

International audienc

Emergence of long-range angular correlations in low-multiplicity proton-proton collisions

International audienceThis Letter presents the measurement of near-side associated per-trigger yields, denoted ridge yields, from the analysis of angular correlations of charged hadrons in proton-proton collisions at $\sqrt{s}$ = 13 TeV. Long-range ridge yields are extracted for pairs of charged particles with a pseudorapidity difference of $1.4 < |\Delta\eta| < 1.8$ and a transverse momentum of $1 < p_{\rm T} < 2$ GeV/$c$, as a function of the charged-particle multiplicity measured at midrapidity. This study extends the measurements of the ridge yield to the low multiplicity region, where in hadronic collisions it is typically conjectured that a strongly-interacting medium is unlikely to be formed. The precision of the new results allows for the first direct quantitative comparison with the results obtained in $\mathrm {e^{+}e^{-}}$ collisions at $\sqrt{s}$ = 91 GeV, where initial-state effects such as pre-equilibrium dynamics and collision geometry are not expected to play a role. In the multiplicity range where the $\mathrm {e^{+}e^{-}}$ results have good precision, the measured ridge yields in pp collisions are substantially larger than the limits set in $\mathrm {e^{+}e^{-}}$ annihilations. Consequently, the findings presented in this Letter suggest that the processes involved in $\mathrm {e^{+}e^{-}}$ annihilations do not contribute significantly to the emergence of long-range correlations in pp collisions

Common femtoscopic hadron-emission source in pp collisions at the LHC

International audienceThe femtoscopic study of pairs of identical pions is particularly suited to investigate the effective source function of particle emission, due to the resulting Bose-Einstein correlation signal. In small collision systems at the LHC, pp in particular, the majority of the pions are produced in resonance decays, which significantly affect the profile and size of the source. In this work, we explicitly model this effect in order to extract the primordial source in pp collisions at $\sqrt{s} = 13$ TeV from charged $\pi$-$\pi$ correlations measured by ALICE. We demonstrate that the assumption of a Gaussian primordial source is compatible with the data and that the effective source, resulting from modifications due to resonances, is approximately exponential, as found in previous measurements at the LHC. The universality of hadron emission in pp collisions is further investigated by applying the same methodology to characterize the primordial source of K-p pairs. The size of the primordial source is evaluated as a function of the transverse mass ($m_{\rm T}$) of the pairs, leading to the observation of a common scaling for both $\pi$-$\pi$ and K-p, suggesting a collective effect. Further, the present results are compatible with the $m_{\rm T}$ scaling of the p-p and p$-\Lambda$ primordial source measured by ALICE in high multiplicity pp collisions, providing compelling evidence for the presence of a common emission source for all hadrons in small collision systems at the LHC. This will allow the determination of the source function for any hadron--hadron pairs with high precision, granting access to the properties of the possible final-state interaction among pairs of less abundantly produced hadrons, such as strange or charmed particles

Photoproduction of K+^{+}K−^{-} pairs in ultra-peripheral collisions

International audienceK$^{+}$K$^{-}$ pairs may be produced in photonuclear collisions, either from the decays of photoproduced $\phi (1020)$ mesons, or directly as non-resonant K$^{+}$K$^{-}$ pairs. Measurements of K$^{+}$K$^{-}$ photoproduction probe the couplings between the $\phi (1020)$ and charged kaons with photons and nuclear targets. We present the first measurement of coherent photoproduction of K$^{+}$K$^{-}$ pairs on lead ions in ultra-peripheral collisions using the ALICE detector, including the first investigation of direct K$^{+}$K$^{-}$ production. There is significant K$^{+}$K$^{-}$ production at low transverse momentum, consistent with coherent photoproduction on lead targets. In the mass range $1.1 < M_{\rm{KK}} < 1.4$ GeV/$c^2$ above the $\phi (1020)$ resonance, for rapidity $|y_{\rm{KK}}|<0.8$ and $p_{\rm T,KK} < 0.1$ GeV/$c$, the measured coherent photoproduction cross section is $\mathrm{d}\sigma/\mathrm{d}y$ = 3.37 $\pm\ 0.61$ (stat.) $\pm\ 0.15$ (syst.) mb. The centre-of-mass energy per nucleon of the photon-nucleus (Pb) system $W_{\gamma \mathrm{Pb, n}}$ ranges from 33 to 188 GeV, far higher than previous measurements on heavy-nucleus targets. The cross section is larger than expected for $\phi (1020)$ photoproduction alone. The mass spectrum is fit to a cocktail consisting of $\phi (1020)$ decays, direct K$^{+}$K$^{-}$ photoproduction, and interference between the two. The confidence regions for the amplitude and relative phase angle for direct K$^{+}$K$^{-}$ photoproduction are presented

Photoproduction of K+^{+}K−^{-} pairs in ultra-peripheral collisions

International audienceK$^{+}$K$^{-}$ pairs may be produced in photonuclear collisions, either from the decays of photoproduced $\phi (1020)$ mesons, or directly as non-resonant K$^{+}$K$^{-}$ pairs. Measurements of K$^{+}$K$^{-}$ photoproduction probe the couplings between the $\phi (1020)$ and charged kaons with photons and nuclear targets. We present the first measurement of coherent photoproduction of K$^{+}$K$^{-}$ pairs on lead ions in ultra-peripheral collisions using the ALICE detector, including the first investigation of direct K$^{+}$K$^{-}$ production. There is significant K$^{+}$K$^{-}$ production at low transverse momentum, consistent with coherent photoproduction on lead targets. In the mass range $1.1 < M_{\rm{KK}} < 1.4$ GeV/$c^2$ above the $\phi (1020)$ resonance, for rapidity $|y_{\rm{KK}}|<0.8$ and $p_{\rm T,KK} < 0.1$ GeV/$c$, the measured coherent photoproduction cross section is $\mathrm{d}\sigma/\mathrm{d}y$ = 3.37 $\pm\ 0.61$ (stat.) $\pm\ 0.15$ (syst.) mb. The centre-of-mass energy per nucleon of the photon-nucleus (Pb) system $W_{\gamma \mathrm{Pb, n}}$ ranges from 33 to 188 GeV, far higher than previous measurements on heavy-nucleus targets. The cross section is larger than expected for $\phi (1020)$ photoproduction alone. The mass spectrum is fit to a cocktail consisting of $\phi (1020)$ decays, direct K$^{+}$K$^{-}$ photoproduction, and interference between the two. The confidence regions for the amplitude and relative phase angle for direct K$^{+}$K$^{-}$ photoproduction are presented