444 research outputs found

    An 8300-yr record of environmental and cultural changes in the St. Eufemia Plain (Calabria, Italy)

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    The landscape evolution of the Sant’Eufemia Plain (Calabria, Italy) in the last 8300 years was reconstructed through integration of pollen data and archaeological evidence within a well-defined paleoenvironmental and chronostratigraphical framework. Pollen analysis of a 24-m core showed that a dense floodplain forest characterized the landscape from ca. 8300 up to ca. 2300 yr cal BP, when human impact becomes evident through intense deforestation, cultivation and fires. Due to the high density of the forest canopy in the plain, few signs of human presence are recorded by pollen in prehistoric and protohistoric periods despite the occurrence of settlements from the Neolithic to the Iron Age. In concurrence with the reduction of wet environments in the plain and the surrounding foothills, major urban centers and villas developed during the Graeco-Roman period, entailing considerable environmental impact. Clear signs of deforestation, recorded through a general reduction of tree taxa, were connected to timber production and trade during the Roman period, as also attested by historical sources. Intensive olive cultivation started in the Early Medieval period, in agreement with other data from central and southern Italy, suggesting that olive oil consumption during the Roman period was not connected to large-scale local production. The Holocene history of this landscape shows that the location of settlements from the Neolithic onward was strongly influenced by the environment, which led people to select more stable, well-drained areas, such as relicts of inactive depositional landforms within or around the plain

    Ask the shark. Blackmouth catshark (Galeus melastomus) as a sentinel of plastic waste on the seabed

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    The presence of plastic waste in the marine environment has driven the scientific community to make significant efforts to study and mitigate its possible effects. One of the critical aspects is to determine if and how an increase in ingestion events may occur as a result of the accumulation of plastic waste on the seabed. In this study, G. melastomus is examined for its ability to indirectly provide information on the amount of macroplastics accumulating on the seafloor. Plastic ingestion is explored by describing the feeding habits of the species, which have the potential to provide very useful information regarding biological or ecological issues. The diet of G. melastomus mainly consisted of cephalopods, bathypelagic fishes, and decapod crustaceans, increasing in diversity during growth. The generalist-opportunistic feeding behaviour of this species leads to the incidental ingestion of plastic particles (N = 47, with a mean (+/- SD) of 1.47 +/- 0.28 per specimen) which can be indirectly associated to the presence of macroplastics on the seafloor. Indeed, our results indicate a significant relationship between the amount of macroplastics present on the seabed and the frequency of ingestion of plastic particles by blackmouth catshark. We propose G. melastomus as an excellent candidate for developing a valid monitoring strategy for the presence of plastics on the seabed, as requested by the EU Marine Strategy Framework Directive

    TORCH physics performance : improving low-momentum PID performance during Upgrade IB and beyond

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    This document details the status of simulation studies for the proposed TORCH detector for operation during Upgrade Ib. The anticipated physics performance in key progresses is presented, alongside a summary of the R&D status. Further studies of interest are outlined

    Status of the TORCH time-of-flight detector

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    TORCH is a novel time-of-flight detector, designed to provide π\pi/K particle identification up to 10 GeV/c\,\text{GeV}/c momentum over a 10 \,m flight path. Based on the DIRC principle, Cherenkov photons are produced in a quartz plate of 10 \,mm thickness, where they propagate to the periphery of the plate by total-internal reflection. There the photons are focused onto an array of micro-channel plate photomultipliers (MCP-PMTs) which measure their arrival times and spatial positions. A time resolution of 70 ps per detected Cherenkov photon is expected, which results in a time-of-flight resolution of 15 ps, given typically 30 detected photons per track. For a future application, a full-scale TORCH detector has been proposed for the future LHCb upgrade, which comprises 18 modules with 198 MCP-PMTs. To demonstrate the TORCH principle, a half-height (1250×660×10 mm31250\times660\times10 \,\text{mm}^3) prototype module has been tested in a 8 GeV/c\,\text{GeV}/c mixed proton-pion beam at the CERN PS. Customised 53×53 mm253\times53\,\text{mm}^2 MCP-PMTs of effective granularity 128×8128\times8 pixels have been employed, which have been developed in collaboration with an industrial partner. The single-photon timing performance and photon yields have been measured and are close to specification, demonstrating the TORCH concept

    Test-beam performance of a TORCH prototype module

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    The TORCH time-of-flight detector is designed to provide a 15 ps timing resolution for charged particles, resulting in K/Ï€K/\pi (p/K)(p/K) particle identification up to momentum of about 10(15) GeV/cc over a 10 m flight distance. Cherenkov photons, produced in a quartz plate of 10 mm thickness, are focused onto an array of micro-channel plate photomultipliers (MCP-PMTs) which measure the photon arrival times and spatial positions. A TORCH demonstrator module instrumented with a customised MCP-PMTs has been tested at the CERN PS. The useful implementation for the particle identification in the LHCb experiment requires single-photon time resolution of 70 ps. The timing performance and photon yields have been measured as a function of beam position in the radiator, giving measurements which are approaching the required resolution. A possible TORCH design of the particle identification system in the LHCb experiment has been simulated and its potential for high luminosity running has been evaluated

    Acceso, democracia y comunidades virtuales : apropiación de tecnologías digitales desde el Cono Sur

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    Es tiempo de empezar a desarrollar tecnologías alternativas que se basen en otros modelos de negocios, en la resolución de otras necesidades, que se configuren con otros procesos, como la construcción colectiva de algoritmos, que sean procesos transparentes y abiertos, que tengan principios comunitarios de manejo de datos. Una tecnología construida por las comunidades y poblaciones que hasta ahora han sido etiquetadas como las grandes consumidoras y que nuestro grupo propone que tengan el derecho de diseñar, definir y proponer la tecnología que requieren y que quieren. Especialmente nos referimos a las mujeres, las poblaciones indígenas, las poblaciones migrantes, fronterizas, costeras, rurales, entre otros. Partimos del principio de que en estos momentos históricos en que vivimos en una sociedad digital, es un derecho humano fundamental que todo grupo social diseñe y construya la tecnología que necesita. Además, estamos convencidos y convencidas de que pueden/podemos hacerlo. Del Pronunciamiento conjunto del Grupo de Trabajo CLACSO Apropiación de Tecnologías Digitales e interseccionalidades y RIAT

    Branching Fraction Measurements of the Rare Bs0→ϕμ+μ−B^0_s\rightarrow\phi\mu^+\mu^- and Bs0→f2′(1525)μ+μ−B^0_s\rightarrow f_2^\prime(1525)\mu^+\mu^- Decays

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    The branching fraction of the rare Bs0→ϕμ+μ−B^0_s\rightarrow\phi\mu^+\mu^- decay is measured using data collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to integrated luminosities of 1, 2, and 6 fb−1^{-1}, respectively. The branching fraction is reported in intervals of q2^2, the square of the dimuon invariant mass. In the q2^2 region between 1.1 and 6.0 GeV2^2/c4^4, the measurement is found to lie 3.6 standard deviations below a standard model prediction based on a combination of light cone sum rule and lattice QCD calculations. In addition, the first observation of the rare Bs0→f2′(1525)μ+μ−B^0_s\rightarrow f_2^\prime(1525)\mu^+\mu^- decay is reported with a statistical significance of 9 standard deviations and its branching fraction is determined

    Study of coherent J/ψJ/\psi production in lead-lead collisions at sNN \sqrt{{\mathrm{s}}_{\mathrm{NN}}} = 5 TeV

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    International audienceCoherent production of J/ψ mesons is studied in ultraperipheral lead-lead collisions at a nucleon-nucleon centre-of-mass energy of 5 TeV, using a data sample collected by the LHCb experiment corresponding to an integrated luminosity of about 10 μb−1^{−1}. The J/ψ mesons are reconstructed in the dimuon final state and are required to have transverse momentum below 1 GeV. The cross-section within the rapidity range of 2.0 < y < 4.5 is measured to be 4.45 ± 0.24 ± 0.18 ± 0.58 mb, where the first uncertainty is statistical, the second systematic and the third originates from the luminosity determination. The cross-section is also measured in J/ψ rapidity intervals. The results are compared to predictions from phenomenological models.[graphic not available: see fulltext

    Measurement of the CKM angle γ\gamma and Bs0-B‾s0{B}_s^0\hbox{-} {\overline{B}}_s^0 mixing frequency with Bs0→Ds∓h±π±π∓{B}_s^0\to {D}_s^{\mp }{h}^{\pm }{\pi}^{\pm }{\pi}^{\mp } decays

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    Measurement of CP Violation in the Decay B+→K+π0B^{+} \rightarrow K^{+} \pi^{0}