524 research outputs found

    STDP in Adaptive Neurons Gives Close-To-Optimal Information Transmission

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    Spike-frequency adaptation is known to enhance the transmission of information in sensory spiking neurons by rescaling the dynamic range for input processing, matching it to the temporal statistics of the sensory stimulus. Achieving maximal information transmission has also been recently postulated as a role for spike-timing-dependent plasticity (STDP). However, the link between optimal plasticity and STDP in cortex remains loose, as does the relationship between STDP and adaptation processes. We investigate how STDP, as described by recent minimal models derived from experimental data, influences the quality of information transmission in an adapting neuron. We show that a phenomenological model based on triplets of spikes yields almost the same information rate as an optimal model specially designed to this end. In contrast, the standard pair-based model of STDP does not improve information transmission as much. This result holds not only for additive STDP with hard weight bounds, known to produce bimodal distributions of synaptic weights, but also for weight-dependent STDP in the context of unimodal but skewed weight distributions. We analyze the similarities between the triplet model and the optimal learning rule, and find that the triplet effect is an important feature of the optimal model when the neuron is adaptive. If STDP is optimized for information transmission, it must take into account the dynamical properties of the postsynaptic cell, which might explain the target-cell specificity of STDP. In particular, it accounts for the differences found in vitro between STDP at excitatory synapses onto principal cells and those onto fast-spiking interneurons

    Operating a full tungsten actively cooled tokamak: overview of WEST first phase of operation

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    WEST is an MA class superconducting, actively cooled, full tungsten (W) tokamak, designed to operate in long pulses up to 1000 s. In support of ITER operation and DEMO conceptual activities, key missions of WEST are: (i) qualification of high heat flux plasma-facing components in integrating both technological and physics aspects in relevant heat and particle exhaust conditions, particularly for the tungsten monoblocks foreseen in ITER divertor; (ii) integrated steady-state operation at high confinement, with a focus on power exhaust issues. During the phase 1 of operation (2017–2020), a set of actively cooled ITER-grade plasma facing unit prototypes was integrated into the inertially cooled W coated startup lower divertor. Up to 8.8 MW of RF power has been coupled to the plasma and divertor heat flux of up to 6 MW m−2 were reached. Long pulse operation was started, using the upper actively cooled divertor, with a discharge of about 1 min achieved. This paper gives an overview of the results achieved in phase 1. Perspectives for phase 2, operating with the full capability of the device with the complete ITER-grade actively cooled lower divertor, are also described

    Multidifferential study of identified charged hadron distributions in ZZ-tagged jets in proton-proton collisions at s=\sqrt{s}=13 TeV

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    Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a ZZ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 <pT<100< p_{\textrm{T}} < 100 GeV and in the pseudorapidity range 2.5<η<42.5 < \eta < 4. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb1^{-1}. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb public pages

    Study of the BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

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    The decay BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} is studied in proton-proton collisions at a center-of-mass energy of s=13\sqrt{s}=13 TeV using data corresponding to an integrated luminosity of 5 fb1\mathrm{fb}^{-1} collected by the LHCb experiment. In the Λc+K\Lambda_{c}^+ K^{-} system, the Ξc(2930)0\Xi_{c}(2930)^{0} state observed at the BaBar and Belle experiments is resolved into two narrower states, Ξc(2923)0\Xi_{c}(2923)^{0} and Ξc(2939)0\Xi_{c}(2939)^{0}, whose masses and widths are measured to be m(Ξc(2923)0)=2924.5±0.4±1.1MeV,m(Ξc(2939)0)=2938.5±0.9±2.3MeV,Γ(Ξc(2923)0)=0004.8±0.9±1.5MeV,Γ(Ξc(2939)0)=0011.0±1.9±7.5MeV, m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV}, where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt Λc+K\Lambda_{c}^{+} K^{-} sample. Evidence of a new Ξc(2880)0\Xi_{c}(2880)^{0} state is found with a local significance of 3.8σ3.8\,\sigma, whose mass and width are measured to be 2881.8±3.1±8.5MeV2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV} and 12.4±5.3±5.8MeV12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}, respectively. In addition, evidence of a new decay mode Ξc(2790)0Λc+K\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-} is found with a significance of 3.7σ3.7\,\sigma. The relative branching fraction of BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} with respect to the BD+DKB^{-} \to D^{+} D^{-} K^{-} decay is measured to be 2.36±0.11±0.22±0.252.36 \pm 0.11 \pm 0.22 \pm 0.25, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

    Measurement of the ratios of branching fractions R(D)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

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    The ratios of branching fractions R(D)B(BˉDτνˉτ)/B(BˉDμνˉμ)\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu}) and R(D0)B(BD0τνˉτ)/B(BD0μνˉμ)\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu}) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb1{ }^{-1} of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τμντνˉμ\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}. The measured values are R(D)=0.281±0.018±0.024\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024 and R(D0)=0.441±0.060±0.066\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is ρ=0.43\rho=-0.43. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

    Santé et hygiène de l'enfant dans l'Egypte ancienne

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    Les connaissances que nous avons de la santé et de l'hygiène de l'enfantdans l'Egypte ancienne, sont issues des informations apportées par les papyrusmédicaux, littéraires ou administratifs et par les objets ou les bas-reliefs desmonuments. Celles-ci permettent de découper l'enfance en deux périodes.Une première période est consacrée aux soins nécessaires à un nourrissondont l'allaitement maternel est l'élément primordial. Les médecins essayeront alorsde le favoriser grâce aux rites magico-religieux et aux remèdes écrits dans lespapyrus médicaux. D'autres traitements seront également utilisés pour traiter desmaladies aux origines obscures comme celles causées par la substance bââ ou lamaladie-temyt. Mais certaines pathologies, touchant le jeune enfant, sont déjà bienreconnues, comme la toux, la rètention urinaire, l'otite ou le coryza.Ensuite, une deuxiéme période s'étend du sevrage de l'enfant à sonadolescence. Le jeune égyptien recevra alors une éducation lui permettant d'acquérir la morale nécessaire pour devenir un bon Egyptien. Il apprendra également les techniques d'écriture, de lecture et les sciences. De plus, son quotidien sera rythmé par le sport et les jeux. Au cours de cette période, les médecins de l'Egypte ancienne utiliseront leur savoir pour traiter les diarrhées, les parasitoses, les maladies ophtalmologiques, les traumatismes et les morsures

    SANTE ET HYGIENE DE L'ENFANT DANS L'EGYPTE ANCIENNE

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    NANCY1-SCD Medecine (545472101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

    Analyse en moyenne d'algorithmes, tri rapide et arbres de recherche

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    SIGLEINIST T 77164 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

    Is Capillary Electrophoresis a New Tool to Monitor Acute Lithium Poisoning in Human?

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    International audienceA 38-year-old man was admitted in the intensive care unit (ICU) after supposed ingestion of 504 sustained-release tablets of Theralithe (TM) corresponding similar to 200 g of lithium carbonate. At the admission, similar to 19.5 h after ingestion, the patient was conscious with trembling limbs, intense thirst, profuse sweats and vomiting and lithium serum concentration was 14.2 mmol/L. Toxicological screenings performed in urine and serum, were negative. Patient was treated with continuous extrarenal epuration by continue veno-venous hemodiafiltration starting (CCVHDF) 24 h post-admission and was carried on until 64 h. After 11 days in ICU, the patient was dismissed to the service without sequelae, and transferred to a psychiatric unit. To follow lithium concentrations in serum, urines and dialysates, we developed a simple, rapid and reliable method by capillary zone electrophoresis (CZE). Separation was achieved in 7 min. The method was linear between 0.14 and 1.44 mmol/L for serum samples, and between 0.07 and to 1.44 mmol/L for urines and dialysates. Limits of quantification were 0.15 mmol/L and 0.07 mmol/L for serum and others fluids, respectively. Intra- and inter-day precisions expressed as CV were systematically inferior to 12.1% for serum and 8.2% for other fluids. Results obtained regarding precision, accuracy, recovery and stability were satisfying, with recoveries ranging from 91.0 to 102.0%. Serum, urine and dialysate samples were measured using CZE and flame photometry. We observed a strong correlation between both methods as assessed by linear regression and Bland-Altman analysis. For the intoxicated patient, the assay was successfully applied to serum, urine and dialysates to determine the amount of lithium present in circulation and excreted. Lithium amounts in dialysates were estimated to correspond to 89% of total lithium excreted during CCVHF session while urine excretion account only for 11%

    Comparative genomics of the Nakaseomyces clade: Candida glabrata and enew merging pathogens

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    All authors wish to acknowledge the work of colleagues and collaborators who are authors of the final paper in preparationInternational audienceC. glabrata has become the second fungal pathogenic agent of human illness after C. albicans, and two new species, C. nivariensis and C. bracarensis, have been described as emerging pathogens from the clade of the Nakaseomyces. We have sequenced these genomes and that of the other three environmental yeasts from the clade. These species share with Saccharomyces the common ancestor which underwent a whole genome duplication. Nonetheless, chromosome number is highly variable in the clade with some low chromosome numbers. Centromeres show less conservation than expected, as do telomeric repeats. All species share genomic and physiological features that define their monophylogeny. These include genome size and gene number, the presence of insertions in non coding RNA genes, loss of genes from metabolic pathways such as GAL and BNA, and absence of active transposable elements. All contain homologs of genes involved in mating, although most species are described as asexual, and all contain a putative HO gene, enabling mating-type switching in Saccharomyces. Indeed, sexual species in the clade are homothallic and may share with S. cerevisiae the HO gene and three duplicated cassettes. Nonetheless, variations are observed in the chromosomal structure of the cassettes. Other features are common only to C. glabrata and closest species. These include duplicated genes encoding ribosomal proteins, for example. We will report on gene family expansions and contractions in species, on specific features of pathogens, and on specificities of C. glabrata, such as tandem amplification of genes involved in virulence
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