13 research outputs found

    Constraining the contribution of Gamma-Ray Bursts to the high-energy diffuse neutrino flux with 10 yr of ANTARES data

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    Addressing the origin of the astrophysical neutrino flux observed by IceCube is of paramount importance. Gamma-Ray Bursts (GRBs) are among the few astrophysical sources capable of achieving the required energy to contribute to such neutrino flux through pγ interactions. In this work, ANTARES data have been used to search for upward going muon neutrinos in spatial and temporal coincidence with 784 GRBs occurred from 2007 to 2017. For each GRB, the expected neutrino flux has been calculated in the framework of the internal shock model and the impact of the lack of knowledge on the majority of source redshifts and on other intrinsic parameters of the emission mechanism has been quantified. It is found that the model parameters that set the radial distance where shock collisions occur have the largest impact on neutrino flux expectations. In particular, the bulk Lorentz factor of the source ejecta and the minimum variability time-scale are found to contribute significantly to the GRB-neutrino flux uncertainty. For the selected sources, ANTARES data have been analysed by maximizing the discovery probability of the stacking sample through an extended maximum-likelihood strategy. Since no neutrino event passed the quality cuts set by the optimization procedure, 90 per cent confidence level upper limits (with their uncertainty) on the total expected diffuse neutrino flux have been derived, according to the model. The GRB contribution to the observed diffuse astrophysical neutrino flux around 100 TeV is constrained to be less than 10 per cent

    Architecture and performance of the KM3NeT front-end firmware

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    The KM3NeT infrastructure consists of two deep-sea neutrino telescopes being deployed in the Mediterranean Sea. The telescopes will detect extraterrestrial and atmospheric neutrinos by means of the incident photons induced by the passage of relativistic charged particles through the seawater as a consequence of a neutrino interaction. The telescopes are configured in a three-dimensional grid of digital optical modules, each hosting 31 photomultipliers. The photomultiplier signals produced by the incident Cherenkov photons are converted into digital information consisting of the integrated pulse duration and the time at which it surpasses a chosen threshold. The digitization is done by means of time to digital converters (TDCs) embedded in the field programmable gate array of the central logic board. Subsequently, a state machine formats the acquired data for its transmission to shore. We present the architecture and performance of the front-end firmware consisting of the TDCs and the state machine

    The IDENTIFY study: the investigation and detection of urological neoplasia in patients referred with suspected urinary tract cancer - a multicentre observational study

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    Objective To evaluate the contemporary prevalence of urinary tract cancer (bladder cancer, upper tract urothelial cancer [UTUC] and renal cancer) in patients referred to secondary care with haematuria, adjusted for established patient risk markers and geographical variation. Patients and Methods This was an international multicentre prospective observational study. We included patients aged ≥16 years, referred to secondary care with suspected urinary tract cancer. Patients with a known or previous urological malignancy were excluded. We estimated the prevalence of bladder cancer, UTUC, renal cancer and prostate cancer; stratified by age, type of haematuria, sex, and smoking. We used a multivariable mixed-effects logistic regression to adjust cancer prevalence for age, type of haematuria, sex, smoking, hospitals, and countries. Results Of the 11 059 patients assessed for eligibility, 10 896 were included from 110 hospitals across 26 countries. The overall adjusted cancer prevalence (n = 2257) was 28.2% (95% confidence interval [CI] 22.3–34.1), bladder cancer (n = 1951) 24.7% (95% CI 19.1–30.2), UTUC (n = 128) 1.14% (95% CI 0.77–1.52), renal cancer (n = 107) 1.05% (95% CI 0.80–1.29), and prostate cancer (n = 124) 1.75% (95% CI 1.32–2.18). The odds ratios for patient risk markers in the model for all cancers were: age 1.04 (95% CI 1.03–1.05; P < 0.001), visible haematuria 3.47 (95% CI 2.90–4.15; P < 0.001), male sex 1.30 (95% CI 1.14–1.50; P < 0.001), and smoking 2.70 (95% CI 2.30–3.18; P < 0.001). Conclusions A better understanding of cancer prevalence across an international population is required to inform clinical guidelines. We are the first to report urinary tract cancer prevalence across an international population in patients referred to secondary care, adjusted for patient risk markers and geographical variation. Bladder cancer was the most prevalent disease. Visible haematuria was the strongest predictor for urinary tract cancer

    Determining the Neutrino Mass Ordering and Oscillation Parameters with KM3NeT/ORCA

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    The KM3NeT/ORCA sensitivity to atmospheric neutrino oscillation is presented. The event reconstruction, selection and classification are described. The sensitivity to determine the neutrino mass ordering was evaluated and found to be 4.4 σ if the true ordering is normal and 2.3 σ if inverted, after three years of data taking. The precision to measure Δm232 and θ23 were also estimated and found to be 85⋅10−6 eV2 and (+1.9−3.1)∘ for normal neutrino mass ordering and, 75⋅10−6 eV2 and (+2.0−7.0)∘ for inverted ordering. Finally, a unitarity test of the leptonic mixing matrix by measuring the rate of tau neutrinos is described. Three years of data taking were found to be sufficient to exclude ντ and ν¯τ event rate variations larger than 20% at 3σ level

    Cyclopentenyl cytosine increases the phosphorylation and incorporation into DNA of 1-beta-D-arabinofuranosyl cytosine in a human T-lymphoblastic cell line

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    The cytotoxic effect of I-P-D-arabinofuranosyl cytosine (araC) depends on the intracellular phosphorylation into its active compound araCTP, on the degree of degradation of araCTP and on the incorporation of araCTP into DNA. Deoxycytidine triphosphate (dCTP) inhibits the phosphorylation of araC (by feedback inhibition of the enzyme deoxycyticline kinase) and the incorporation of araCTP into DNA (by competition for DNA polymerase). In a T-lymphoblastic cell line, we studied whether the cytotoxicity of araC (2 nM-50 muM) could be enhanced by decreasing the concentration of dCTP, using the nucleoside-analogue cyclopentenyl cytosine (CPEC), an inhibitor of the enzyme CTP synthetase. Preincubation of the cells with CPEC (100-1,600 nM) for 2 hr increased the concentrations of araCMP 1.6-9.5-fold, which was significant for each concentration of CPEC used. The concentration of araCDP remained low, whereas the concentration of araCTP changed depending on the concentration of araC used. With 2-15 muM of araC and a preincubation with 400 nM of CPEC, the araCTP concentration increased by 4 -15% (not significant), and the total amount of araC nucleotides increased significantly by 21-45%. When using a concentration of araC of 2 nM after a preincubation with CPEC of 100 nM, the concentration of araCMP increased by 60% (p = 0.015), whereas that of araCTP decreased by 10% (p = 0.008). This was compensated by an increase of 41% (p = 0.005) of araCTP incorporation into DNA, which represented 43% of all araC metabolites. Moreover, by performing pulse/chase experiments with 400 nM of CPEC and 2muM of araC, the retention of cytosolic araCTP and the incorporated amount of araCTP into DNA were increased by CPEC. The modulation by CPEC of araC metabolism was accompanied by a synergistic increase of araC-induced apoptosis and by an additive effect on the araC-induced growth inhibition. (C) 2002 Wiley-Liss, In

    Etude des facteurs de risque du retard de croissance intra-utérin à lubumbashi

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    Introduction: Dans notre milieu, il n'existe aucune politique de prévention du Retard de Croissance Intra-Utérin (RCIU) clairement défini. L'objectif de ce travail était d'identifier les facteurs de risque de RCIU afin de proposer une stratégie de lutte contre cette pathologie en agissant surtout sur des facteurs pouvant faire l'objet d'une action préventive. Méthodes: Une étude cas-témoins a été menée dans 11 centres hospitaliers de Lubumbashi en République Démocratique du Congo, de Janvier 2010 à Juin 2011, dans le but d'identifier les facteurs de risque du retard de croissance intra-utérin (RCIU). Au total 420 gestantes (cas et témoins) avec grossesse monofoetale d'au moins 24 semaines d'aménorrhée ont été inclues dans l'étude. Les cas correspondaient aux gestantes dont le poids du fœtus était resté inférieur au 10 eme percentile des courbes de référence d'Alexander, après 2 échographies successives réalisées à intervalle de 4 semaines. Les témoins correspondaient aux gestantes dont le poids du fœtus était supérieur ou égal au 10 eme percentile de mêmes courbes. A chaque cas a été apparié un témoin de même parité porteur d'une grossesse de même âge. Résultats: L'analyse univariée a identifié comme facteurs de risque: la taille maternelle <155 cm (OR=2, 45 (1, 17-5, 10)) et l' âge maternel <18 ans (OR=2, 88 (1, 12-7, 74)), le bas niveau socio-économique (OR=2, 53(1, 76-4, 23)), le mauvais état nutritionnel (OR=1, 96 (1, 20-3, 19)), l'espace inter génésique inferieur à 12 mois (OR=1, 92 (1, 02 -3, 63)), l'hypertension artérielle (OR=2, 44 (1, 32-4, 55)), le paludisme (OR=1, 95 (1, 26-3, 00))et l'anémie sévère (OR=2, 28 (1, 21-4, 34)). L'analyse multi variée a permis de retenir les facteurs de risque suivants: la taille maternelle <155cm (OR=3, 93 (1, 61-9, 61)), le niveau socio-économique bas (OR=5, 33 (2, 57-11, 04)), l'hypertension artérielle (OR=4, 64 (2, 25-9, 59)) et le paludisme (OR=2, 26 (2, 25-4, 20)). Conclusion: L'amélioration du niveau socio-économique des populations, la lutte contre le paludisme et les consultations prénatales mieux organisées couplées à une meilleure éducation sanitaire et nutritionnelle peuvent contribuer sensiblement à la réduction de la fréquence du RCIU à Lubumbashi

    Indirect dark matter searches with the ANTARES and KM3NeT neutrino telescopes

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    Neutrino telescopes perform an indirect search for dark matter (DM) through its annihilation into standard model channels yielding neutrinos, for a broad range of WIMP masses. The ANTARES detector, anchored to the Mediterranean seabed at a depth of about 2500 m, looks for a DM signal from two promising neutrino sources from WIMP annihilation: the Galactic Center and the Sun. We present the latest results on ANTARES indirect detection in a wide range of WIMP masses and decay channels, and give a future prospect on sensitivities of DM searches with the KM3NeT detector, the next-generation neutrino telescope, currently under deployment in the Mediterranean Sea. These experiments have specific advantages, complementary to other detection strategies, and can provide a smoking-gun signal. The geographical location of ANTARES and KM3NeT is particularly well suited for searches in the Galactic Center, allowing for the world-best sensitivity for WIMP annihilation

    Imaging the neural circuitry and chemical control of aggressive motivation

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    <p>Abstract</p> <p>Background</p> <p>With the advent of functional magnetic resonance imaging (fMRI) in awake animals it is possible to resolve patterns of neuronal activity across the entire brain with high spatial and temporal resolution. Synchronized changes in neuronal activity across multiple brain areas can be viewed as functional neuroanatomical circuits coordinating the thoughts, memories and emotions for particular behaviors. To this end, fMRI in conscious rats combined with 3D computational analysis was used to identifying the putative distributed neural circuit involved in aggressive motivation and how this circuit is affected by drugs that block aggressive behavior.</p> <p>Results</p> <p>To trigger aggressive motivation, male rats were presented with their female cage mate plus a novel male intruder in the bore of the magnet during image acquisition. As expected, brain areas previously identified as critical in the organization and expression of aggressive behavior were activated, e.g., lateral hypothalamus, medial basal amygdala. Unexpected was the intense activation of the forebrain cortex and anterior thalamic nuclei. Oral administration of a selective vasopressin V<sub>1a </sub>receptor antagonist SRX251 or the selective serotonin reuptake inhibitor fluoxetine, drugs that block aggressive behavior, both caused a general suppression of the distributed neural circuit involved in aggressive motivation. However, the effect of SRX251, but not fluoxetine, was specific to aggression as brain activation in response to a novel sexually receptive female was unaffected.</p> <p>Conclusion</p> <p>The putative neural circuit of aggressive motivation identified with fMRI includes neural substrates contributing to emotional expression (i.e. cortical and medial amygdala, BNST, lateral hypothalamus), emotional experience (i.e. hippocampus, forebrain cortex, anterior cingulate, retrosplenial cortex) and the anterior thalamic nuclei that bridge the motor and cognitive components of aggressive responding. Drugs that block vasopressin neurotransmission or enhance serotonin activity suppress activity in this putative neural circuit of aggressive motivation, particularly the anterior thalamic nuclei.</p
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