2,997 research outputs found
Ecosystem functioning and ecological status in the Venice lagoon, which relationships?
The implementation of management measures for improving the ecological status within an Ecosystem Based Management approach represents one the of the main challenges in coastal and transitional water environments. In general terms, ecological status and ecosystem functioning are expected to be positively associated, being good ecological processes a sort of prerequisite for the ecosystem health, but often relationships between ecosystem functioning indicators and the metrics used to define ecological status resulted to be rather puzzling. Moreover, the Biological Quality Elements (BQEs) do not show a consistent response to the changes in the ecosystem. This situation does not allow to recognize where interventions are really needed, hindering the definition of effective management strategies. In the present paper, a spatially explicit food web model of the Venice lagoon (with the resolution of 300 m) is used to simulate changes in the ecological status and related them to different management scenarios. Functional changes in the food web were investigated by comparing values of a set of 12 indicators derived by the ecological network analysis. In general, results highlighted on one hand the need for more discussion about the implementation of the WFD, at least in complex and spatially heterogeneous transitional waters environments, as the Venice lagoon; on the other, results remark the opportunity to support the BQEs monitoring with an ecological modelling approach. These models are certainly not the panacea for addressing questions about the environmental management, as they have inherent uncertainties (on parameters, structure, processes etc.); however, they can prove useful for selecting among different policy choices, since they offer the opportunity to simulate the mean effects, preliminarily verifying the efficacy of the proposed interventions
A didactic experiment to measure the angular correlation between
A didactic experiment carried out by a group of Physics masters’ students at Bari University is presented. The purpose was the study of the angular correlation between the two gamma rays of 1.17 MeV and 1.33 MeV emitted in typical 60Co decays by means of two NaI(Tl) scintillators equipped with photomultiplier tubes read out by a digital oscilloscope. Several runs were performed with the Co
source at different angles between the two scintillators. Additional runs were performed removing the source, to study the backgrounds from cosmic rays and from gamma rays emitted by the radioactive isotopes 208Tl and 40K. Our results showed that the signal rate changes with the angular separation in agreement with the theoretical expectations by Hamilton dating back to 1940 and with recent measurements
documented in the literature. Students learned to plan and set up an experiment, to take data and to perform basic analysis. Care was taken to understand the limits of our experimental apparatus and possible improvements
IRF4 expression is low in Philadelphia negative myeloproliferative neoplasms and is associated with a worse prognosis
Interferon regulatory factor 4 (IRF4) is involved in the pathogenesis of various hematologic malignancies. Its expression has been related to the negative regulation of myeloid-derived suppressor cells (MDSCs) and the polarization of anti-inflammatory M2 macrophages, thereby altering immunosurveillance and inflammatory mechanisms. An abnormal inflammatory status in the bone marrow microenvironment of myeloproliferative neoplasms (MPNs) has recently been demonstrated; moreover, in chronic myeloid leukemia a downregulated expression of IRF4 has been found. In this context, we evaluated the IRF4 expression in 119 newly diagnosed consecutive Philadelphia negative MPNs (Ph- MPNs), showing a low expression among the MPNs phenotypes with a more significant decrease in primary myelofibrosis patients. Lower IRF4 levels were associated with JAK2 + and triple negatives cases carrying the worst prognosis. Furthermore, the IRF4 levels were related to leukemic transformation and a shorter leukemia-free survival; moreover, the risk of myelofibrosis transformation in polycythemia vera and essential thrombocythemia patients was more frequent in cases with lower IRF4 levels. Overall, our study demonstrates an IRF4 dysregulated expression in MPNs patients and its association with a worse prognosis. Further studies could validate these data, to improve our knowledge of the MPNs pathogenesis and confirm the IRF4 role as a new prognostic factor
Multi-GeV Electron Spectrometer
The advance in laser plasma acceleration techniques pushes the regime of the
resulting accelerated particles to higher energies and intensities. In
particular the upcoming experiments with the FLAME laser at LNF will enter the
GeV regime with almost 1pC of electrons. From the current status of
understanding of the acceleration mechanism, relatively large angular and
energy spreads are expected. There is therefore the need to develop a device
capable to measure the energy of electrons over three orders of magnitude (few
MeV to few GeV) under still unknown angular divergences. Within the PlasmonX
experiment at LNF a spectrometer is being constructed to perform these
measurements. It is made of an electro-magnet and a screen made of
scintillating fibers for the measurement of the trajectories of the particles.
The large range of operation, the huge number of particles and the need to
focus the divergence present unprecedented challenges in the design and
construction of such a device. We will present the design considerations for
this spectrometer and the first results from a prototype.Comment: 7 pages, 6 figures, submitted to NIM
Nanopore sequencing approach for immunoglobulin gene analysis in chronic lymphocytic leukemia
The evaluation of the somatic hypermutation of the clonotypic immunoglobulin heavy variable gene has become essential in the therapeutic management in chronic lymphocytic leukemia patients. European Research Initiative on Chronic Lymphocytic Leukemia promotes good practices and standardized approaches to this assay but often they are labor-intensive, technically complex, with limited in scalability. The use of next-generation sequencing in this analysis has been widely tested, showing comparable accuracy and distinct advantages. However, the adoption of the next generation sequencing requires a high sample number (run batching) to be economically convenient, which could lead to a longer turnaround time. Here we present data from nanopore sequencing for the somatic hypermutation evaluation compared to the standard method. Our results show that nanopore sequencing is suitable for immunoglobulin heavy variable gene mutational analysis in terms of sensitivity, accuracy, simplicity of analysis and is less time-consuming. Moreover, our work showed that the development of an appropriate data analysis pipeline could lower the nanopore sequencing error rate attitude
Beam Test Performance and Simulation of Prototypes for the ALICE Silicon Pixel Detector
The silicon pixel detector (SPD) of the ALICE experiment in preparation at
the Large Hadron Collider (LHC) at CERN is designed to provide the precise
vertex reconstruction needed for measuring heavy flavor production in heavy ion
collisions at very high energies and high multiplicity. The SPD forms the
innermost part of the Inner Tracking System (ITS) which also includes silicon
drift and silicon strip detectors. Single assembly prototypes of the ALICE SPD
have been tested at the CERN SPS using high energy proton/pion beams in 2002
and 2003. We report on the experimental determination of the spatial precision.
We also report on the first combined beam test with prototypes of the other ITS
silicon detector technologies at the CERN SPS in November 2004. The issue of
SPD simulation is briefly discussed.Comment: 4 pages, 5 figures, prepared for proceedings of 7th International
Position Sensitive Detectors Conference, Liverpool, Sept. 200
Measurement of the front-end dead-time of the LHCb muon detector and evaluation of its contribution to the muon detection inefficiency
A method is described which allows to deduce the dead-time of the front-end
electronics of the LHCb muon detector from a series of measurements performed
at different luminosities at a bunch-crossing rate of 20 MHz. The measured
values of the dead-time range from 70 ns to 100 ns. These results allow to
estimate the performance of the muon detector at the future bunch-crossing rate
of 40 MHz and at higher luminosity
Performance of ALICE pixel prototypes in high energy beams
The two innermost layers of the ALICE inner tracking system are instrumented
with silicon pixel detectors. Single chip assembly prototypes of the ALICE
pixels have been tested in high energy particle beams at the CERN SPS.
Detection efficiency and spatial precision have been studied as a function of
the threshold and the track incidence angle. The experimental method, data
analysis and main results are presented.Comment: 10 pages, 9 figures, contribution to PIX2005 Workshop, Bonn
(Germany), 5-8 September 200
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