University of Basilicata

About: University of Basilicata is a education organization based out in Potenza, Italy. It is known for research contribution in the topics: Large Hadron Collider & Population. The organization has 2044 authors who have published 6732 publications receiving 175392 citations. The organization is also known as: Università degli Studi della Basilicata & Universita degli Studi della Basilicata.

GW190425: Observation of a Compact Binary Coalescence with Total Mass ∼ 3.4 M O

Abstract: On 2019 April 25, the LIGO Livingston detector observed a compact binary coalescence with signal-to-noise ratio 12.9. The Virgo detector was also taking data that did not contribute to detection due to a low signal-to-noise ratio, but were used for subsequent parameter estimation. The 90% credible intervals for the component masses range from to if we restrict the dimensionless component spin magnitudes to be smaller than 0.05). These mass parameters are consistent with the individual binary components being neutron stars. However, both the source-frame chirp mass and the total mass of this system are significantly larger than those of any other known binary neutron star (BNS) system. The possibility that one or both binary components of the system are black holes cannot be ruled out from gravitational-wave data. We discuss possible origins of the system based on its inconsistency with the known Galactic BNS population. Under the assumption that the signal was produced by a BNS coalescence, the local rate of neutron star mergers is updated to 250-2810.

The human footprint in the carbon cycle of temperate and boreal forests

Abstract: A study of forest ecosystems from across western Europe and the United States has settled a long-running controversy — and raised many new questions. At issue is the influence of nitrogen deposition on the global carbon cycle, particularly the part played by human activity. The new study demonstrates that via the direct effects of forest management and indirectly via the use of nitrogen fertilizers and nitrogen oxide production by cars and industry, human activities have had a profound and largely positive effect on the carbon balance or net ecosystem production. (That's the balance between ecosystem carbon fixation through photosynthesis and its subsequent release through plant and soil respiration.) The implications of these findings for practical questions such as the merits of fertilizing forests with nitrogen, are considered in the accompanying News and Views by Peter Hogberg. The profound, overwhelming effects of human activities on the carbon balance of temperate and boreal forests are demonstrated. Apart from the direct effects of forest management, they show that carbon sequestration by this important component of the biosphere is driven by the imbalance in the global nitrogen cycle determined by human activities. Temperate and boreal forests in the Northern Hemisphere cover an area of about 2 × 107 square kilometres and act as a substantial carbon sink (0.6–0.7 petagrams of carbon per year)1. Although forest expansion following agricultural abandonment is certainly responsible for an important fraction of this carbon sink activity, the additional effects on the carbon balance of established forests of increased atmospheric carbon dioxide, increasing temperatures, changes in management practices and nitrogen deposition are difficult to disentangle, despite an extensive network of measurement stations2,3. The relevance of this measurement effort has also been questioned4, because spot measurements fail to take into account the role of disturbances, either natural (fire, pests, windstorms) or anthropogenic (forest harvesting). Here we show that the temporal dynamics following stand-replacing disturbances do indeed account for a very large fraction of the overall variability in forest carbon sequestration. After the confounding effects of disturbance have been factored out, however, forest net carbon sequestration is found to be overwhelmingly driven by nitrogen deposition, largely the result of anthropogenic activities5. The effect is always positive over the range of nitrogen deposition covered by currently available data sets, casting doubts on the risk of widespread ecosystem nitrogen saturation6 under natural conditions. The results demonstrate that mankind is ultimately controlling the carbon balance of temperate and boreal forests, either directly (through forest management) or indirectly (through nitrogen deposition).

RoadRunner: Towards Automatic Data Extraction from Large Web Sites

Abstract: The paper investigates techniques for extracting data from HTML sites through the use of automatically generated wrappers. To automate the wrapper generation and the data extraction process, the paper develops a novel technique to compare HTML pages and generate a wrapper based on their similarities and dierences. Experimental results on real-life data-intensive Web sites confirm the feasibility of the approach.

Determination of jet energy calibration and transverse momentum resolution in CMS

Abstract: Measurements of the jet energy calibration and transverse momentum resolution in CMS are presented, performed with a data sample collected in proton-proton collisions at a centre-of-mass energy of 7TeV, corresponding to an integrated luminosity of 36pb−1. The transverse momentum balance in dijet and γ/Z+jets events is used to measure the jet energy response in the CMS detector, as well as the transverse momentum resolution. The results are presented for three different methods to reconstruct jets: a calorimeter-based approach, the ``Jet-Plus-Track'' approach, which improves the measurement of calorimeter jets by exploiting the associated tracks, and the ``Particle Flow'' approach, which attempts to reconstruct individually each particle in the event, prior to the jet clustering, based on information from all relevant subdetectors

Particle-flow reconstruction and global event description with the CMS detector

Abstract: The CMS apparatus was identified, a few years before the start of the LHC operation at CERN, to feature properties well suited to particle-flow (PF) reconstruction: a highly-segmented tracker, a fine-grained electromagnetic calorimeter, a hermetic hadron calorimeter, a strong magnetic field, and an excellent muon spectrometer. A fully-fledged PF reconstruction algorithm tuned to the CMS detector was therefore developed and has been consistently used in physics analyses for the first time at a hadron collider. For each collision, the comprehensive list of final-state particles identified and reconstructed by the algorithm provides a global event description that leads to unprecedented CMS performance for jet and hadronic τ decay reconstruction, missing transverse momentum determination, and electron and muon identification. This approach also allows particles from pileup interactions to be identified and enables efficient pileup mitigation methods. The data collected by CMS at a centre-of-mass energy of 8\TeV show excellent agreement with the simulation and confirm the superior PF performance at least up to an average of 20 pileup interactions.