478 research outputs found
Environmental DNA metabarcoding reveals the effects of seafloor litter and trawling on marine biodiversity
Environmental DNA (eDNA) techniques are emerging as promising tools for monitoring marine communities. However, they have not been applied to study the integrated effects of anthropogenic pressures on marine biodiversity. This study examined the relationships between demersal community species composition, key environmental features, and anthropogenic impacts such as fishing effort and seafloor litter using eDNA data in the central Tyrrhenian Sea. The results indicated that both fishing effort and seafloor litter influenced species composition and diversity. The adaptive traits of marine species played a critical role in their response to debris accumulation and fishing. Mobile species appeared to use relocation strategies, while sessile species showed flexibility in the face of disturbance. Epibiotic species relied on passive transport. The use of eDNA-based methods is a valuable resource for monitoring anthropogenic impacts during scientific surveys, enhancing our ability to monitor marine ecosystems and more effectively assess the effects of pollution
Study of the decay
The decay is studied
in proton-proton collisions at a center-of-mass energy of TeV
using data corresponding to an integrated luminosity of 5
collected by the LHCb experiment. In the system, the
state observed at the BaBar and Belle experiments is
resolved into two narrower states, and ,
whose masses and widths are measured to be where the first uncertainties are statistical and the second
systematic. The results are consistent with a previous LHCb measurement using a
prompt sample. Evidence of a new
state is found with a local significance of , whose mass and width
are measured to be and , respectively. In addition, evidence of a new decay mode
is found with a significance of
. The relative branching fraction of with respect to the
decay is measured to be , 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 and
The ratios of branching fractions
and are measured, assuming isospin symmetry, using a
sample of proton-proton collision data corresponding to 3.0 fb of
integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The
tau lepton is identified in the decay mode
. The measured values are
and
, where the first uncertainty is
statistical and the second is systematic. The correlation between these
measurements is . 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
Multidifferential study of identified charged hadron distributions in -tagged jets in proton-proton collisions at 13 TeV
Jet fragmentation functions are measured for the first time in proton-proton
collisions for charged pions, kaons, and protons within jets recoiling against
a boson. The charged-hadron distributions are studied longitudinally and
transversely to the jet direction for jets with transverse momentum 20 GeV and in the pseudorapidity range . 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 fb. 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
An 8300-yr record of environmental and cultural changes in the St. Eufemia Plain (Calabria, Italy)
The landscape evolution of the SantâEufemia 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
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
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
TORCH is a novel time-of-flight detector, designed to provide /K particle identification up to 10 momentum over a 10m flight path. Based on the DIRC principle, Cherenkov photons are produced in a quartz plate of 10mm 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 () prototype module has been tested in a 8 mixed proton-pion beam at the CERN PS. Customised MCP-PMTs of effective granularity 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
The TORCH time-of-flight detector is designed to provide a 15 ps timing resolution for charged particles, resulting in particle identification up to momentum of about 10(15) GeV/ 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 : apropiaciĂłn de tecnologĂas digitales desde el Cono Sur
Es tiempo de empezar a desarrollar tecnologĂas alternativas que se basen en otros modelos de negocios, en la resoluciĂłn de otras necesidades, que se configuren con otros procesos, como la construcciĂłn colectiva de algoritmos, que sean procesos transparentes y abiertos, que tengan principios comunitarios de manejo de datos.
Una tecnologĂa 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 tecnologĂa que requieren y que quieren. Especialmente nos referimos a las mujeres, las poblaciones indĂgenas, las poblaciones migrantes, fronterizas, costeras, rurales, entre otros. Partimos del principio de que en estos momentos histĂłricos en que vivimos en una sociedad digital, es un derecho humano fundamental que todo grupo social diseñe y construya la tecnologĂa que necesita. AdemĂĄs, estamos convencidos y convencidas de que pueden/podemos hacerlo.
Del Pronunciamiento conjunto del Grupo de Trabajo CLACSO ApropiaciĂłn de TecnologĂas Digitales e interseccionalidades y RIAT
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