State selective cooling of SU(N)\mathrm{SU}(N) Fermi-gases

We investigate a species selective cooling process of a trapped $\mathrm{SU}(N)$ Fermi gas using entropy redistribution during adiabatic loading of an optical lattice. Using high-temperature expansion of the Hubbard model, we show that when a subset $N_A < N$ of the single-atom levels experiences a stronger trapping potential in a certain region of space, the dimple, it leads to improvement in cooling as compared to a $\mathrm{SU}(N_A)$ Fermi gas only. We show that optimal performance is achieved when all atomic levels experience the same potential outside the dimple and we quantify the cooling for various $N_A$ by evaluating the dependence of the final entropy densities and temperatures as functions of the initial entropy. Furthermore, considering ${}^{87}{\rm Sr}$ and ${}^{173}{\rm Yb}$ for specificity, we provide a quantitative discussion of how the state selective trapping can be achieved with readily available experimental techniques.Comment: 8+3 pages, 4+1 figure

Asteroid target selection for the new Rosetta mission baseline: 21 Lutetia and 2867 Steins

Reproduced with permission. Copyright ESO. Article published by EDP Sciences and available at http://www.aanda.org.International audienceThe new Rosetta mission baseline to the comet 67P/Churyumov-Gerasimenko includes two asteroid fly-bys. To help in target selection we studied all the candidates of all the possible scenarios. Observations have been carried out at ESO-NTT (La Silla, Chile), TNG (Canaries), and NASA-IRTF (Hawaii) telescopes, in order to determine the taxonomy of all the candidates. The asteroid targets were chosen after the spacecraft interplanetary orbit insertion manoeuvre, when the available total amount of ΔV was known. On the basis of our analysis and the available of ΔV, we recommended to the ESA ScienceWorking Group the asteroids 21 Lutetia and 2867 Steins as targets for the Rosetta mission. The nature of Lutetia is still controversial. Lutetia's spectral properties may be consistent with a composition similar to carbonaceous chondrite meteorites. The spectral properties of Steins suggest a more extensive thermal history. Steins may have a composition similar to relatively rare enstatite chondrite/achondrite meteorites

A perfect palindrome in the Escherichia coli chromosome forms DNA hairpins on both leading- and lagging-strands

DNA palindromes are hotspots for DNA double strand breaks, inverted duplications and intra-chromosomal translocations in a wide spectrum of organisms from bacteria to humans. These reactions are mediated by DNA secondary structures such as hairpins and cruciforms. In order to further investigate the pathways of formation and cleavage of these structures, we have compared the processing of a 460 base pair (bp) perfect palindrome in the Escherichia coli chromosome with the same construct interrupted by a 20 bp spacer to form a 480 bp interrupted palindrome. We show here that the perfect palindrome can form hairpin DNA structures on the templates of the leading- and lagging-strands in a replication-dependent reaction. In the presence of the hairpin endonuclease SbcCD, both copies of the replicated chromosome containing the perfect palindrome are cleaved, resulting in the formation of an unrepairable DNA double-strand break and cell death. This contrasts with the interrupted palindrome, which forms a hairpin on the lagging-strand template that is processed to form breaks, which can be repaired by homologous recombination

Minimum wages in 2023 : annual review

Aquesta publicació s'elabora a partir de les contribucions de cadascú dels membres nacionals que integren la Network of Eurofound Correspondents. Pel cas d'Espanya la contribució ha estat realitzada per l'Oscar Molina (veure annex Network of Eurofound Correspondents)The 2023 annual review of minimum wages was prepared in the context of unprecedented inflation across Europe. While this led to hefty increases in nominal wage rates in many countries, it was in many cases not enough to maintain workers' purchasing power. Based on developments over the last decade, this report shows that, overall, minimum wage earners in nearly all countries saw their purchasing power rising, the gap between their wages and average wages narrowing, and to some degree growth exceeding labour productivity development

Measurement of nuclear modification factors of gamma(1S)), gamma(2S), and gamma(3S) mesons in PbPb collisions at root s(NN)=5.02 TeV

The cross sections for ϒ(1S), ϒ(2S), and ϒ(3S) production in lead-lead (PbPb) and proton-proton (pp) collisions at √sNN = 5.02 TeV have been measured using the CMS detector at the LHC. The nuclear modification factors, RAA, derived from the PbPb-to-pp ratio of yields for each state, are studied as functions of meson rapidity and transverse momentum, as well as PbPb collision centrality. The yields of all three states are found to be significantly suppressed, and compatible with a sequential ordering of the suppression, RAA(ϒ(1S)) > RAA(ϒ(2S)) > RAA(ϒ(3S)). The suppression of ϒ(1S) is larger than that seen at √sNN = 2.76 TeV, although the two are compatible within uncertainties. The upper limit on the RAA of ϒ(3S) integrated over pT, rapidity and centrality is 0.096 at 95% confidence level, which is the strongest suppression observed for a quarkonium state in heavy ion collisions to date. © 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.Peer reviewe

Electroweak production of two jets in association with a Z boson in proton-proton collisions root s =13 TeV

A measurement of the electroweak (EW) production of two jets in association with a Z boson in proton-proton collisions at root s = 13 TeV is presented, based on data recorded in 2016 by the CMS experiment at the LHC corresponding to an integrated luminosity of 35.9 fb(-1). The measurement is performed in the lljj final state with l including electrons and muons, and the jets j corresponding to the quarks produced in the hard interaction. The measured cross section in a kinematic region defined by invariant masses m(ll) > 50 GeV, m(jj) > 120 GeV, and transverse momenta P-Tj > 25 GeV is sigma(EW) (lljj) = 534 +/- 20 (stat) fb (syst) fb, in agreement with leading-order standard model predictions. The final state is also used to perform a search for anomalous trilinear gauge couplings. No evidence is found and limits on anomalous trilinear gauge couplings associated with dimension-six operators are given in the framework of an effective field theory. The corresponding 95% confidence level intervals are -2.6 <cwww/Lambda(2) <2.6 TeV-2 and -8.4 <cw/Lambda(2) <10.1 TeV-2. The additional jet activity of events in a signal-enriched region is also studied, and the measurements are in agreement with predictions.Peer reviewe

Etude des processus physiques qui gouvernent l'évolution des petits corps glacés du système solaire

Among the icy bodies of the solar system, we find the transneptunian objects (TNO) and centaurs. Centaurs orbit between Jupiter and Saturn while TNOS orbit, most of the time, beyond Neptune. These objects are mainly composed of ices but their chemical properties are not well known. I performed observations devoted to the investigation of these objects surfaces, using photometry and spectroscopy. Both of these dynamical populations are composed of objects that show different spectra in visible and near infrared wavelengths. Visible slopes can be very steep, suggesting the presence of organic compounds. The existence of such material imply irradiation processes. I analyzed spectra using several radiative transfer theories and laboratory data. Many absorption bands indicate the presence of water ice and even methane ice on the biggest ones. The biggest objects seem to have more ice on their surface than the smallest ones. So, mechanisms that govern the evolution of the object surfaces have different efficiency depending on the object size. (Cryo-volcanism, non-disruptive collision) or on the heliocentric distances (cometary activity). I determined the ices physical state of different ices like water ice and methane, pure diluted in nitrogen. These species, highly volatile, are only observed on the large objects, where gravity is big enough to retain them. I finally constrain the surface temperature of two objects from spectral thermometers. The work carried out during my thesis strongly contributed to a better understanding of these objects, introducing new constraints on their surface properties and on the probable physical processes that modified them.Parmi les corps glacés du système solaire, on trouve les objets trans-neptuniens (OTNS) et les centaures. Alors que les centaures orbitent aux voisinages de Jupiter et de Saturne, les OTNS orbitent au delà de Neptune. Ces objets sont composés en grande partie de glace, mais leur composition exacte reste inconnue. J'ai réalisé des observations (photométrie et spectroscopie) pour étudier la surface de ces objets. Les deux populations dynamiques étudiées sont composées d'objets dont les spectres dans le visible et le proche infrarouge sont très variés. Les gradients spectraux peuvent être très élevés, trahissant la présence probable de composés organiques. Ces composés impliquent des processus d'irradiation. J'ai analysé les spectres par le biais de différents modèles de transfert radiatif et de données de laboratoire. Les nombreuses bandes d'absorption indiquent que la majorité des objets possède de la glace d'eau en surface, voire de la glace de méthane pour les plus gros OTNS. Les mécanismes qui gouvernent l'évolution de la surface de ces objets ont différents degrés d'efficacité qui dépend de la taille des objets (cryo-volcanisme, collisions) et de leurs distances héliocentriques (activité cométaire). J'ai déterminé l'état physique de différentes glaces comme l'eau ou le méthane (pur ou dilué dans l'azote). Ces espèces très volatiles sont uniquement observées sur les plus gros objets ou la gravité est assez importante pour les retenir. J'ai finalement contraint la température de surface de deux objets par l'intermédiaire de thermomètres spectraux. Ce travail a ainsi contribué à mieux contraindre leurs propriétés de surface et les processus physiques qui les gouvernent

Etude des processus physiques qui gouvernent l'évolution des petits corps glacés du système solaire

Parmi les corps glacés du système solaire, on trouve les objets trans-neptuniens (OTNS) et les centaures. Alors que les centaures orbitent aux voisinages de Jupiter et de Saturne, les OTNS orbitent au delà de Neptune. Ces objets sont composés en grande partie de glace, mais leur composition exacte reste inconnue. J'ai réalisé des observations (photométrie et spectroscopie) pour étudier la surface de ces objets. Les deux populations dynamiques étudiées sont composées d'objets dont les spectres dans le visible et le proche infrarouge sont très variés. Les gradients spectraux peuvent être très élevés, trahissant la présence probable de composés organiques. Ces composés impliquent des processus d'irradiation. J'ai analysé les spectres par le biais de différents modèles de transfert radiatif et de données de laboratoire. Les nombreuses bandes d'absorption indiquent que la majorité des objets possède de la glace d'eau en surface, voire de la glace de méthane pour les plus gros OTNS. Les mécanismes qui gouvernent l'évolution de la surface de ces objets ont différents degrés d'efficacité qui dépend de la taille des objets (cryo-volcanisme, collisions) et de leurs distances héliocentriques (activité cométaire). J'ai déterminé l'état physique de différentes glaces comme l'eau ou le méthane (pur ou dilué dans l'azote). Ces espèces très volatiles sont uniquement observées sur les plus gros objets ou la gravité est assez importante pour les retenir. J'ai finalement contraint la température de surface de deux objets par l'intermédiaire de thermomètres spectraux. Ce travail a ainsi contribué à mieux contraindre leurs propriétés de surface et les processus physiques qui les gouvernent.PARIS-Observatoire (751142302) / SudocSudocFranceF

Near-Infrared Spectroscopy of 133P/Elst-Pizarro

International audienc