585 research outputs found

    Progress towards Bell-type polarization experiment with thermal neutrons

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    Experimental tests of Bell-type inequalities distinguishing between quantum mechanics and local realistic theories remain of considerable interest if performed on massive particles, for which no conclusive result has yet been obtained. Only two-particle experiments may specifically test the concept of spatial nonlocality in quantum theory, whereas single-particle experiments may generally test the concept of quantum noncontextuality. Here we have performed the first Bell-type experiment with a beam of thermal-neutron pairs in the singlet state of spin, as originally suggested by J. S. Bell. These measurements confirm the quantum-theoretical predictions, in agreement with the results of the well-known polarization experiments carried out on optical photons years ago

    Further evidence of antibunching of two coherent beams of fermions

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    We describe an experiment confirming the evidence of the antibunching effect on a beam of non interacting thermal neutrons. The comparison between the results recorded with a high energy-resolution source of neutrons and those recorded with a broad energy-resolution source enables us to clarify the role played by the beam coherence in the occurrence of the antibunching effect.Comment: 4 pages, 3 figure

    ELMB Microcontroller Firmware and SCADA Integration for the LHCb Muon Detector Readout Control System

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    The LHCb system requires high efficiency muon detection into LHC bunch crossing: 95% into a 25 ns time window. To reach such efficiency many parameters of the detector readout apparatus have to be calibrated and adjusted and its channels must be aligned in time. In addition, essential characteristics must be monitored to guarantee a good working condition of the apparatus (to avoid loss of efficiency and to minimize systematic errors). As the number of the muon readout parameters is extremely high (∌700000 registers), a system able to process information in parallel is required: 122000 readout channels will be controlled by about 600 microcontrollers and 6 computers. The complexity of such an apparatus requires the use of a distributed system. For this a Supervisory Control And Data Acquisition (SCADA) based system is being developed to control the entire detector readout equipment. Moreover, a Finite State Machine (FSM) implementation is being developed to integrate the Detector Readout Control (DRC) into the LHC Experiment Control System (ECS)

    Foraging behaviour of Apis mellifera adansonii and its impact on pollination, fruit and seed yields of Citrullus lanatus at Nkolbisson (Yaoundé, Cameroon)

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    Honeybee (Apis mellifera adansonii Latreille (Hymenoptera: Apidae)) foraging activity was observed to evaluate its impact on pollination, fruit and seed yields of Citrullus lanatus (Thunb) Mansf (Cucurbitaceae) in the area of YaoundĂ© (Cameroon). Two lots of 775 female flowers were marked according to the presence or the absence of a protection for insect visits. The honey bees’ activity, the fruit set, the number of seeds per fruit were recorded. A. m. adansonii primarily foraged for nectar on C. lanatus throughout the whole blooming period of each plant and pollen collection was low. The mean maximum number of workers foraging at the same time was 331 ± 173 (n= 41) per 1000 flowers. The mean foraging speed was 10.20 ± 2.75 (n = 154) flowers per minute. The fruit set and the number of seeds per fruit of unprotected female flowers were significantly higher than those of female flowers protected from insects. A. m. adansonii pollination contributed 70.14% to the fruit set and seed yields. The conservation of A. m. adansonii colonies near C. lanatus population must be encouraged.Key words: Citrullus lanatus, Apis mellifera adansonii, pollination, yields, Cameroon.L’activitĂ© de butinage d’Apis mellifera adansonii Latreille (Hymenoptera : Apidae) a Ă©tĂ© Ă©tudiĂ©e afin d’évaluer son impact sur la pollinisation, les rendements fruitiers et grainiers de Citrullus lanatus (Thunb) Mansf (Cucurbitaceae) Ă  YaoundĂ© (Cameroun). Deux lots ont Ă©tĂ© dĂ©terminĂ©s par le marquage de 775 fleurs femelles diffĂ©rant selon la prĂ©sence ou l’absence de protection vis-Ă -vis des visites d’insectes. Le rythme saisonnier d’activitĂ© des abeilles domestiques, le taux de fructification des fleurs femelles et le nombre de graines par fruit ont Ă©tĂ© Ă©valuĂ©s. A. m. adansonii butinait les fleurs de C. lanatus tout au long de la pĂ©riode de floraison de chaque plante. Les butineuses prĂ©levaient intensĂ©ment le nectar pendant que la collecte du pollen Ă©tait rĂ©duite. Le plus grand nombre d’ouvriĂšres butinant simultanĂ©ment Ă©tait de 331 ± 173 (n = 41)par 1000 fleurs. La vitesse moyenne de butinage Ă©tait de 10.20 ± 2.75 (n = 154) fleurs par minute. Le taux de fructification et le nombre moyen de graines matures par fruit des fleurs non protĂ©gĂ©es de l’activitĂ© des insectes Ă©taient significativement Ă©levĂ©s que ceux des fleurs femelles protĂ©gĂ©es. La contribution d’A. m. adansonii sur les rendements fruitiers et grainiers de C. lanatus Ă©tait de 70.14% grĂące Ă  l’action pollinisatrice des ouvriĂšres. La conservation des colonies d’A. m. adansonii Ă  cĂŽtĂ© des populations de C. lanatus en fleurs doit ĂȘtre encouragĂ©e.Mots clĂ©s: Citrullus lanatus, Apis mellifera adansonii, pollinisation, rendements, Camerou

    Antifungal Activity and DNA Topoisomerase Inhibition of Hydrolysable Tannins from Punica granatum L

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    Punica granatum L. (pomegranate) fruit is known to be an important source of bioactive phenolic compounds belonging to hydrolysable tannins. Pomegranate extracts have shown antifungal activity, but the compounds responsible for this activity and their mechanism/s of action have not been completely elucidated up to now. The aim of the present study was the investigation of the inhibition ability of a selection of pomegranate phenolic compounds (i.e., punicalagin, punicalin, ellagic acid, gallic acid) on both plant and human fungal pathogens. In addition, the biological target of punicalagin was identified here for the first time. The antifungal activity of pomegranate phenolics was evaluated by means of Agar Disk Diffusion Assay and minimum inhibitory concentration (MIC) evaluation. A chemoinformatic analysis predicted for the first time topoisomerases I and II as potential biological targets of punicalagin, and this prediction was confirmed by in vitro inhibition assays. Concerning phytopathogens, all the tested compounds were effective, often similarly to the fungicide imazalil at the label dose. Particularly, punicalagin showed the lowest MIC for Alternaria alternata and Botrytis cinerea, whereas punicalin was the most active compound in terms of growth control extent. As for human pathogens, punicalagin was the most active compound among the tested ones against Candida albicans reference strains, as well as against the clinically isolates. UHPLC coupled with HRMS indicated that C. albicans, similarly to the phytopathogen Coniella granati, is able to hydrolyze both punicalagin and punicalin as a response to the fungal attack. Punicalagin showed a strong inhibitory activity, with IC50 values of 9.0 and 4.6 ”M against C. albicans topoisomerases I and II, respectively. Altogether, the results provide evidence that punicalagin is a valuable candidate to be further exploited as an antifungal agent in particular against human fungal infections

    Antifungal Activity and DNA Topoisomerase Inhibition of Hydrolysable Tannins from Punica granatum L

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    Punica granatum L. (pomegranate) fruit is known to be an important source of bioactive phenolic compounds belonging to hydrolysable tannins. Pomegranate extracts have shown antifungal activity, but the compounds responsible for this activity and their mechanism/s of action have not been completely elucidated up to now. The aim of the present study was the investigation of the inhibition ability of a selection of pomegranate phenolic compounds (i.e., punicalagin, punicalin, ellagic acid, gallic acid) on both plant and human fungal pathogens. In addition, the biological target of punicalagin was identified here for the first time. The antifungal activity of pomegranate phenolics was evaluated by means of Agar Disk Diffusion Assay and minimum inhibitory concentration (MIC) evaluation. A chemoinformatic analysis predicted for the first time topoisomerases I and II as potential biological targets of punicalagin, and this prediction was confirmed by in vitro inhibition assays. Concerning phytopathogens, all the tested compounds were effective, often similarly to the fungicide imazalil at the label dose. Particularly, punicalagin showed the lowest MIC for Alternaria alternata and Botrytis cinerea, whereas punicalin was the most active compound in terms of growth control extent. As for human pathogens, punicalagin was the most active compound among the tested ones against Candida albicans reference strains, as well as against the clinically isolates. UHPLC coupled with HRMS indicated that C. albicans, similarly to the phytopathogen Coniella granati, is able to hydrolyze both punicalagin and punicalin as a response to the fungal attack. Punicalagin showed a strong inhibitory activity, with IC50 values of 9.0 and 4.6 ”M against C. albicans topoisomerases I and II, respectively. Altogether, the results provide evidence that punicalagin is a valuable candidate to be further exploited as an antifungal agent in particular against human fungal infections

    u-RANIA: a neutron detector based on \mu -RWELL technology

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    In the framework of the ATTRACT-uRANIA project, funded by the European Community, we are developing an innovative neutron imaging detector based on micro-Resistive WELL (Ό\mu -RWELL) technology. The Ό\mu -RWELL, based on the resistive detector concept, ensuring an efficient spark quenching mechanism, is a highly reliable device. It is composed by two main elements: a readout-PCB and a cathode. The amplification stage for this device is embedded in the readout board through a resistive layer realized by means of an industrial process with DLC (Diamond-Like Carbon). A thin layer of B4_4C on the copper surface of the cathode allows the thermal neutrons detection through the release of 7^7Li and α\alpha particles in the active volume. This technology has been developed to be an efficient and convenient alternative to the 3^3He shortage. The goal of the project is to prove the feasibility of such a novel neutron detector by developing and testing small planar prototypes with readout boards suitably segmented with strip or pad read out, equipped with existing electronics or readout in current mode. Preliminary results from the test with different prototypes, showing a good agreement with the simulation, will be presented together with construction details of the prototypes and the future steps of the project.Comment: Prepared for the INSTR20 Conference Proceeding for JINS
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