557 research outputs found

    Isotopic difference in the heteronuclear loss rate in a two-species surface trap

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    We have realized a two-species mirror-magneto-optical trap containing a mixture of 87^{87}Rb (85^{85}Rb) and 133^{133}Cs atoms. Using this trap, we have measured the heteronuclear collisional loss rate ÎČRb−Csâ€Č\beta_{Rb-Cs}' due to intra-species cold collisions. We find a distinct difference in the magnitude and intensity dependence of ÎČRb−Csâ€Č\beta_{Rb-Cs}' for the two isotopes 87^{87}Rb and 85^{85}Rb which we attribute to the different ground-state hyperfine splitting energies of the two isotopes.Comment: 4 pages, 2 figure

    Bioclimatology, structure, and conservation perspectives of Quercus pyrenaica, Acer opalus subsp. Granatensis, and Corylus avellana deciduous forests on Mediterranean bioclimate in the South-Central part of the Iberian Peninsula

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    The plant variability in the southern Iberian Peninsula consists of around 3500 different taxa due to its high bioclimatic, geographic, and geological diversity. The deciduous forests in the southern Iberian Peninsula are located in regions with topographies and specific bioclimatic conditions that allow for the survival of taxa that are typical of cooler and wetter bioclimatic regions and therefore represent the relict evidence of colder and more humid paleoclimatic conditions. The floristic composition of 421 samples of deciduous forests in the south-central part of the Iberian Peninsula were analyzed. The ecological importance index (IVI) was calculated, where the most important tree species were Quercuspyrenaica, Aceropalus subsp. Granatensis, and Corylusavellana. These species are uncommon in the south-central part of the Iberian Peninsula, forming forests of little extension. An analysis of the vertical distribution of the species (stratum) shows that the majority of the species of stratum 3 (hemicriptophics, camephytes, geophites, and nanophanerophytes) are characteristic of deciduous forests, and their presence is positively correlated with high values of bioclimatic variables related to humidity and presence of water in the soil (nemoral environments), while they are negatively correlated with high values of bioclimatic variables related to high temperatures, evapotranspiration, and aridity. This work demonstrates that several characteristic deciduous forest taxa are more vulnerable to disappearance due to the loss of their nemoral conditions caused by gaps in the tree or shrub canopy. These gaps lead to an increase in evapotranspiration, excess insolation, and a consequent loss of water and humidity in the microclimatic conditions.info:eu-repo/semantics/publishedVersio

    On the injectivity of the circular Radon transform arising in thermoacoustic tomography

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    The circular Radon transform integrates a function over the set of all spheres with a given set of centers. The problem of injectivity of this transform (as well as inversion formulas, range descriptions, etc.) arises in many fields from approximation theory to integral geometry, to inverse problems for PDEs, and recently to newly developing types of tomography. The article discusses known and provides new results that one can obtain by methods that essentially involve only the finite speed of propagation and domain dependence for the wave equation.Comment: To appear in Inverse Problem

    Extracellular vesicles : where the amyloid precursor protein carboxyl-terminal fragments accumulate and amyloid-ÎČ oligomerizes

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    Pleiotropic roles are proposed for brain extracellular vesicles (EVs) in the development of Alzheimer's disease (AD). Our previous studies have suggested a beneficial role for EVs in AD, where the endosomal system in vulnerable neurons is compromised, contributing to the removal of accumulated material from neurons. However, the involvement of EVs in propagating AD amyloidosis throughout the brain has been considered because the amyloid-ÎČ precursor protein (APP), APP metabolites, and key APP cleaving enzymes were identified in association with EVs. Here, we undertook to determine whether the secretase machinery is actively processing APP in EVs isolated from the brains of wild-type and APP overexpressing Tg2576 mice. We found that full-length APP is cleaved in EVs incubated in the absence of cells. The resulting metabolites, both α- and ÎČ-APP carboxyl-terminal fragments and APP intracellular domain accumulate in EVs over time and amyloid-ÎČ dimerizes. Thus, EVs contribute to the removal from neurons and transport of APP-derived neurotoxic peptides. While this is potentially a venue for propagation of the pathology throughout the brain, it may contribute to efficient removal of neurotoxic peptides from the brain

    Conseil-santé dans la médecine de premier recours, partie 2

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    Les maladies non transmissibles (MNT, en anglais «non-communicable diseases») ont gagnĂ© du terrain dans le monde entier. Les approches de conseil fourni au cabinet mĂ©dical ont dĂ©jĂ  Ă©tĂ© prĂ©sentĂ©es dans un premier article. Le prĂ©sent article se consacre aux conditions permettant Ă  ces approches de dĂ©ployer leur efficacitĂ© au niveau de la population. Ceci est illustrĂ© sur la base des programmes suisses actuels «Vivre sans tabac», PAPRICA et «Coaching Santé» ainsi que de l’exemple historique «Ça dĂ©bouche sur quoi?»

    Characterization of Lactococcus strains isolated from artisanal Oaxaca cheese

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    Lactococci strains obtained from raw-milk Oaxaca cheese through its production process in two factories from the Tulancingo Valley, Mexico, were isolated and characterized. A total of 120 colonies were selected from the growth in M17 and MRS agars. Twenty were identified as lactococci strains, all Lactococcus lactis, and were characterized by molecular and phenotypic methods including carbohydrate use, enzymatic profile, acidifying capacity, and antibiotic and phage resistance. High phenotypic diversity was observed and confirmed among the Lactococcus lactis strains by rep-PCR fingerprints. Fifty percent of the strains were resistant to streptomycin and 35% to erythromycin. Nine isolates were considered as fast acidifying strains. The predominant volatile compounds produced were 3-methylbutanol, 3-methylbutanal and butane-2,3-dione. A selection of strains isolated in this study has shown satisfactory characteristics to be used as potential starters for the industrial production of Oaxaca cheese.Peer reviewe

    LHC Optics Measurement with Proton Tracks Detected by the Roman Pots of the TOTEM Experiment

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    Precise knowledge of the beam optics at the LHC is crucial to fulfil the physics goals of the TOTEM experiment, where the kinematics of the scattered protons is reconstructed with the near-beam telescopes -- so-called Roman Pots (RP). Before being detected, the protons' trajectories are influenced by the magnetic fields of the accelerator lattice. Thus precise understanding of the proton transport is of key importance for the experiment. A novel method of optics evaluation is proposed which exploits kinematical distributions of elastically scattered protons observed in the RPs. Theoretical predictions, as well as Monte Carlo studies, show that the residual uncertainty of this optics estimation method is smaller than 0.25 percent.Comment: 20 pages, 11 figures, 5 figures, to be submitted to New J. Phy

    Elastic Scattering and Total Cross-Section in p+p reactions measured by the LHC Experiment TOTEM at sqrt(s) = 7 TeV

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    Proton-proton elastic scattering has been measured by the TOTEM experiment at the CERN Large Hadron Collider at s=7\sqrt{s} = 7 TeV in special runs with the Roman Pot detectors placed as close to the outgoing beam as seven times the transverse beam size. The differential cross-section measurements are reported in the |t|-range of 0.36 to 2.5 GeV^2. Extending the range of data to low t values from 0.02 to 0.33 GeV^2,and utilizing the luminosity measurements of CMS, the total proton-proton cross section at sqrt(s) = 7 TeV is measured to be (98.3 +- 0.2(stat) +- 2.8(syst)) mb.Comment: Proceedings of the XLI International Symposium on Multiparticle Dynamics. Accepted for publication in Prog. Theor. Phy

    Double diffractive cross-section measurement in the forward region at LHC

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    The first double diffractive cross-section measurement in the very forward region has been carried out by the TOTEM experiment at the LHC with center-of-mass energy of sqrt(s)=7 TeV. By utilizing the very forward TOTEM tracking detectors T1 and T2, which extend up to |eta|=6.5, a clean sample of double diffractive pp events was extracted. From these events, we measured the cross-section sigma_DD =(116 +- 25) mub for events where both diffractive systems have 4.7 <|eta|_min < 6.5 .Comment: 5 pages, 1 figure, submitted for publicatio

    Performance of the TOTEM Detectors at the LHC

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    The TOTEM Experiment is designed to measure the total proton-proton cross-section with the luminosity-independent method and to study elastic and diffractive pp scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the interaction point IP5, two tracking telescopes, T1 and T2, are installed on each side of the IP in the pseudorapidity region 3.1 < = |eta | < = 6.5, and special movable beam-pipe insertions - called Roman Pots (RP) - are placed at distances of +- 147 m and +- 220 m from IP5. This article describes in detail the working of the TOTEM detector to produce physics results in the first three years of operation and data taking at the LHC.Comment: 40 pages, 31 figures, submitted to Int. J. Mod. Phys.
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