| 1. |
- Perret, J., et al.
(author)
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Time to refine the geography of biodiversity hotspots by integrating molecular data: The Mediterranean Basin as a case study
- 2023
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In: Biological Conservation. - 0006-3207. ; 284
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Journal article (peer-reviewed)abstract
- Three decades ago, worldwide biodiversity hotspots were founded on the distributions of continental plants and vertebrates. Here, we question the timeliness of refining the geography of hotspots by basing their definition on more taxa, thanks to the molecular data available for hyper-diverse organisms such as insects, fungi and marine biota.To do so, we assess the temporal dynamic of molecular data acquisition and the geography of knowledge about lineages currently included or not into hotspot definition. Using the Mediterranean Basin hotspot as a case study, we examine the taxonomic and geographical facets of 175,828 DNA sequences distributed over 21,552 species, and 13,001 indexed biodiversity publications. We reveal a deeply fractured repartition of biodiversity research efforts within the hotspot regarding both barcoding efforts and publication activity, the northern side of the Mediterranean concentrating 84.16 % of the publications and 75.99 % of the public DNA sequences. In addition, 57.55 % of the sequences belong to lineages which were excluded from hotspots definition, with highly congruent geographical patterns among marine and continental lineages.Based on this analysis, we suggest 1) using the uneven geography of knowledge to rebalance sampling efforts towards poorly known regions within the Mediterranean hotspot, 2) handling the molecular corpus of orphan lineages to feed forthcoming multi-taxa biodiversity assessment initiatives, in order to 3) refine the geography of
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| 2. |
- Dufour, Paul, et al.
(author)
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The Yellow-browed Warbler (Phylloscopus inornatus) as a model to understand vagrancy and its potential for the evolution of new migration routes
- 2022
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In: Movement Ecology. - : Springer Science and Business Media LLC. - 2051-3933. ; 10:1
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Journal article (peer-reviewed)abstract
- Why and how new migration routes emerge remain fundamental questions in ecology, particularly in the context of current global changes. In its early stages, when few individuals are involved, the evolution of new migration routes can be easily confused with vagrancy, i.e. the occurrence of individuals outside their regular breeding, non-breeding or migratory distribution ranges. Yet, vagrancy can in theory generate new migration routes if vagrants survive, return to their breeding grounds and transfer their new migration route to their offspring, thus increasing a new migratory phenotype in the population. Here, we review the conceptual framework and empirical challenges of distinguishing regular migration from vagrancy in small obligate migratory passerines and explain how this can inform our understanding of migration evolution. For this purpose, we use the Yellow-browed Warbler (Phylloscopus inornatus) as a case study. This Siberian species normally winters in southern Asia and its recent increase in occurrence in Western Europe has become a prominent evolutionary puzzle. We first review and discuss available evidence suggesting that the species is still mostly a vagrant in Western Europe but might be establishing a new migration route initiated by vagrants. We then list possible empirical approaches to check if some individuals really undertake regular migratory movements between Western Europe and Siberia, which would make this species an ideal model for studying the links between vagrancy and the emergence of new migratory routes.
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| 3. |
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| 4. |
- Adam, J., et al.
(author)
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Search for weakly decaying (Lambda n)over-bar and Lambda Lambda exotic bound states in central Pb-Pb collisions at root S-NN=2.76 TeV
- 2016
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In: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 752, s. 267-277
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Journal article (peer-reviewed)abstract
- We present results of a search for two hypothetical strange dibaryon states, i.e. the H-dibaryon and the possible (Lambda n) over bar bound state. The search is performed with the ALICE detector in central (0-10%) Pb-Pb collisions at root S-NN = 2.76 TeV, by invariant mass analysis in the decay modes (Lambda n) over bar (d) over bar pi(+) and H-dibaryon -> Lambda p pi(-). No evidence for these bound states is observed. Upper limits are determined at 99% confidence level for a wide range of lifetimes and for the full range of branching ratios. The results are compared to thermal, coalescence and hybrid UrQMD model expectations, which describe correctly the production of other loosely bound states, like the deuteron and the hypertriton. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V.
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| 5. |
- Abelev, B., et al.
(author)
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Charged jet cross sections and properties in proton-proton collisions at root s=7 TeV
- 2015
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In: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 91:11
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Journal article (peer-reviewed)abstract
- The differential charged jet cross sections, jet fragmentation distributions, and jet shapes are measured in minimum bias proton-proton collisions at center-of-mass energy root s = 7 TeV using the ALICE detector at the LHC. Jets are reconstructed from charged particle momenta in the midrapidity region using the sequential recombination k(T) and anti-k(T) as well as the SISCone jet finding algorithms with several resolution parameters in the range R = 0.2-0.6. Differential jet production cross sections measured with the three jet finders are in agreement in the transverse momentum (p(T)) interval 20 < p(T)(jet,ch) < 100 GeV/c. They are also consistent with prior measurements carried out at the LHC by the ATLAS Collaboration. The jet charged particle multiplicity rises monotonically with increasing jet p(T), in qualitative agreement with prior observations at lower energies. The transverse profiles of leading jets are investigated using radial momentum density distributions as well as distributions of the average radius containing 80% (< R-80 >) of the reconstructed jet p(T). The fragmentation of leading jets with R = 0.4 using scaled p(T) spectra of the jet constituents is studied. The measurements are compared to model calculations from event generators (PYTHIA, PHOJET, HERWIG). The measured radial density distributions and < R-80 > distributions are well described by the PYTHIA model (tune Perugia-2011). The fragmentation distributions are better described by HERWIG.
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| 6. |
- Abelev, B., et al.
(author)
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Elliptic flow of identified hadrons in Pb-Pb collisions at root(NN)-N-s=2.76 Tev
- 2015
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In: Journal of High Energy Physics. - 1029-8479. ; :6
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Journal article (peer-reviewed)abstract
- The elliptic flow coefficient (v(2)) of identified particles in Pb-Pb collisions at root s(NN) = 2.76 TeV was measured with the ALICE detector at the Large Hadron Collider (LHC). The results were obtained with the Scalar Product method, a two-particle correlation technique, using a pseudo-rapidity gap of |Delta eta| > 0.9 between the identified hadron under study and the reference particles. The v (2) is reported for pi(+/-), K-+/-, K-S(0), p+(p) over bar, phi, Lambda+(Lambda) over bar, Xi+(Xi) over bar (+) and Omega(-)+(Omega) over bar (+) in several collision centralities. In the low transverse momentum (p(T)) region, p(T) < 3 GeV/c, v(2)(p(T)) exhibits a particle mass dependence consistent with elliptic flow accompanied by the transverse radial expansion of the system with a common velocity field. The experimental data for pi (+/-) and the combined K-+/- and K-S(0) results, are described fairly well by hydrodynamic calculations coupled to a hadronic cascade model (VISHNU) for central collisions. However, the same calculations fail to reproduce the v(2)(p(T)) for p+(p) over bar, phi, Lambda+(Lambda) over bar, Xi+(Xi) over bar (+). For transverse momentum values larger than about 3 GeV/c, particles tend to group according to their type, i.e. mesons and baryons. The present measurements exhibit deviations from the number of constituent quark (NCQ) scaling at the level of +/- 20% for p(T) > 3 GeV/c.
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| 7. |
- Abelev, B., et al.
(author)
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Inclusive photon production at forward rapidities in proton-proton collisions at root s=0.9, 2.76 and 7 TeV
- 2015
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In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 75:4
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Journal article (peer-reviewed)abstract
- The multiplicity and pseudorapidity distributions of inclusive photons have been measured at forward rapidities (2.3 < eta < 3.9) in proton-proton collisions at three center-of-mass energies, root s = 0.9, 2.76 and 7 TeV using the ALICE detector. It is observed that the increase in the average photon multiplicity as a function of beam energy is compatible with both a logarithmic and a power-law dependence. The relative increase in average photon multiplicity produced in inelastic pp collisions at 2.76 and 7 TeV center-of-mass energies with respect to 0.9 TeV are 37.2 +/- 0.3% (stat) +/- 8.8% (sys) and 61.2 +/- 0.3% (stat) +/- 7.6% (sys), respectively. The photon multiplicity distributions for all center-of-mass energies are well described by negative binomial distributions. The multiplicity distributions are also presented in terms of KNO variables. The results are compared to model predictions, which are found in general to underestimate the data at large photon multiplicities, in particular at the highest center-of-mass energy. Limiting fragmentation behavior of photons has been explored with the data, but is not observed in the measured pseudorapidity range.
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| 8. |
- Abelev, B., et al.
(author)
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K*(892)(0) and phi(1020) production in Pb-Pb collisions at root s(NN)=2.76 TeV
- 2015
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 91:2
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Journal article (peer-reviewed)abstract
- The yields of the K*(892)(0) and phi(1020) resonances are measured in Pb-Pb collisions at root s(NN) = 2.76 TeV through their hadronic decays using the ALICE detector. The measurements are performed in multiple centrality intervals at mid-rapidity (vertical bar y vertical bar < 0.5) in the transverse-momentum ranges 0.3 < p(T) < 5 GeV/c for the K*(892)(0) and 0.5 < p(T) < 5 GeV/c for the phi(1020). The yields of K*(892)(0) are suppressed in central Pb-Pb collisions with respect to pp and peripheral Pb-Pb collisions (perhaps due to rescattering of its decay products in the hadronic medium), while the longer-lived phi(1020) meson is not suppressed. These particles are also used as probes to study the mechanisms of particle production. The shape of the pT distribution of the phi(1020) meson, but not its yield, is reproduced fairly well by hydrodynamic models for central Pb-Pb collisions. In central Pb-Pb collisions at low and intermediate p(T), the p/phi(1020) ratio is flat in p(T), while the p/pi and phi(1020)/pi ratios show a pronounced increase and have similar shapes to each other. These results indicate that the shapes of the p(T) distributions of these particles in central Pb-Pb collisions are determined predominantly by the particle masses and radial flow. Finally, phi(1020) production in Pb-Pb collisions is enhanced, with respect to the yield in pp collisions and the yield of charged pions, by an amount similar to the Lambda and Xi.
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| 9. |
- Abelev, B., et al.
(author)
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Measurement of electrons from semileptonic heavy-flavor hadron decays in pp collisions at root s=2.76 TeV
- 2015
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In: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 91:1
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Journal article (peer-reviewed)abstract
- The p(T)-differential production cross section of electrons from semileptonic decays of heavy-flavor hadrons has been measured at midrapidity in proton-proton collisions at root s = 2.76 TeV in the transverse momentum range 0.5 < p(T) < 12 GeV/c with the ALICE detector at the LHC. The analysis was performed using minimum bias events and events triggered by the electromagnetic calorimeter. Predictions from perturbative QCD calculations agree with the data within the theoretical and experimental uncertainties.
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| 10. |
- Abelev, B., et al.
(author)
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Multiplicity dependence of jet-like two-particle correlation structures in p-Pb collisions at root s(NN)=5.02 TeV
- 2015
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In: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 741, s. 38-50
-
Journal article (peer-reviewed)abstract
- Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 < p(T),(assoc) < p(T),(trig) < 5.0 GeV/c is examined, to include correlations induced by jets originating from low momentum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range vertical bar eta vertical bar < 0.9. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton-parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p-Pb collisions. Further, the number scales only in the intermediate multiplicity region with the number of binary nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).
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