3,532 research outputs found

    Quantum probes to assess correlations in a composite system

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    We suggest and demonstrate experimentally a strategy to obtain relevant information about a composite system by only performing measurements on a small and easily accessible part of it, which we call quantum probe. We show in particular how quantitative information about the angular correlations of couples of entangled photons generated by spontaneous parametric down conversion is accessed through the study of the trace distance between two polarization states evolved from different initial conditions. After estimating the optimal polarization states to be used as quantum probe, we provide a detailed analysis of the connection between the increase of the trace distance above its initial value and the amount of angular correlations.Comment: 6 pages, 4 figure

    A large dynamic range radiation-tolerant analog memory in a quarter- micron CMOS technology

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    An analog memory prototype containing 8*128 cells has been designed in a commercial quarter-micron CMOS process. The aim of this work is to investigate the possibility of designing large dynamic range mixed-mode switched capacitor circuits for high-energy physics (HEP) applications in deep submicron CMOS technologies. Special layout techniques have been used to make the circuit radiation tolerant. The memory cells employ gate-oxide capacitors for storage, permitting a very high density. A voltage write-voltage read architecture has been chosen to minimize the sensitivity to absolute capacitor values. The measured input voltage range is 2.3 V (the power supply voltage V/sub DD/ is equal to 2.5 V), with a linearity of almost 8 bits over 2 V. The dynamic range is more than 11 bits. The pedestal variation is +or-0.5 mV peak-to-peak. The noise measured, which is dominated by the noise of the measurement setup, is around 0.8 mV rms. The characteristics of the memory have been measured before irradiation and after 100 kGy (SiO/sub 2/), and they do not degrade after irradiation. (15 refs)

    TCP throughput guarantee in the DiffServ Assured Forwarding service: what about the results?

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    Since the proposition of Quality of Service architectures by the IETF, the interaction between TCP and the QoS services has been intensively studied. This paper proposes to look forward to the results obtained in terms of TCP throughput guarantee in the DiffServ Assured Forwarding (DiffServ/AF) service and to present an overview of the different proposals to solve the problem. It has been demonstrated that the standardized IETF DiffServ conditioners such as the token bucket color marker and the time sliding window color maker were not good TCP traffic descriptors. Starting with this point, several propositions have been made and most of them presents new marking schemes in order to replace or improve the traditional token bucket color marker. The main problem is that TCP congestion control is not designed to work with the AF service. Indeed, both mechanisms are antagonists. TCP has the property to share in a fair manner the bottleneck bandwidth between flows while DiffServ network provides a level of service controllable and predictable. In this paper, we build a classification of all the propositions made during these last years and compare them. As a result, we will see that these conditioning schemes can be separated in three sets of action level and that the conditioning at the network edge level is the most accepted one. We conclude that the problem is still unsolved and that TCP, conditioned or not conditioned, remains inappropriate to the DiffServ/AF service

    The First Year of the Large Hadron Collider: A Brief Review

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    The first year of LHC data taking provided an integrated luminosity of about 35/pb in proton-proton collisions at sqrt(s)=7 TeV. The accelerator and the experiments have demonstrated an excellent performance. The experiments have obtained important physics results in many areas, ranging from tests of the Standard Model to searches for new particles. Among other results the physics highlights have been the measurements of the W-, Z-boson and t t-bar production cross-sections, improved limits on supersymmetric and other hypothetical particles and the observation of jet-quenching, elliptical flow and J/Psi suppression in lead-lead collisions at sqrt(sNN) = 2.76 TeV.Comment: 11 pages, 9 figures, invited brief review for Mod. Phys. Lett.

    Nouvel Oriocrassatellinae du Pennsylvanien du BrĂ©sil et distribution spatio-temporelle d’Oriocrassatella

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    Oriocrassatella Etheridge Jr., 1907 is a long range crassatellid bivalve genus well recognized in shallow waters of epeiric seas throughout the upper part of Paleozoic. The first occurrences of this genus are recorded in the sedimentary successions of the Gondwana, both in Australia and South America. However, the geographic and age distribution of Oriocrassatella in Late Mississippian deposits of Australia and Argentina may indicate an earliest Visean or even a pre-Visean origin for the genus. Following its origin in Early Carboniferous a complex paleobiogeographic history from Southern to Northern Hemisphere took place in the Permian. During its initial dispersal phase from Late Carboniferous to the Early Permian the genus thrived in cold water environments associated to the Late Paleozoic Gondwana glaciation. Shallow-water bottoms of the warm waters of the central Gondwana fringe and Laurussia were colonized by Oriocrassatella only during Early Permian times when the genus became cosmopolitan. A new species of this genus is described herein, Oriocrassatella piauiensis n.   sp., recorded from the PiauĂ­ Formation, Pennsylvanian of the ParnaĂ­ba Basin. This new species may represent an early adaptation to warm waters. However, based on available data, species of this genus seem to have adapted definitely to warm water environments probably related the Late Pennsylvanian interglacial phases. In these phases, climatic barrier were interrupted allowing the faunal interchange and larval dispersion following a South to North migration route through the eastern margins of Gondwana and the eastern Paleotethys.Oriocrassatella Etheridge Jr., 1907 est un crassatellidĂ© Ă  large distribution stratigraphique, bien connu dans les mers Ă©picontinentales en eaux peu profondes, caractĂ©ristique du PalĂ©ozoĂŻque supĂ©rieur. Ce genre apparaĂźt pour la premiĂšre fois dans des dĂ©pĂŽts sĂ©dimentaires du Gondwana, en Australie et en AmĂ©rique du Sud. D’aprĂšs sa distribution spatio-temporelle dans des dĂ©pĂŽts du Mississippien supĂ©rieur, Oriocrassatella serait originaire du dĂ©but du VisĂ©en, ou mĂȘme prĂ©-visĂ©enne. Par la suite, depuis le CarbonifĂšre infĂ©rieur jusqu’au Permien, ce genre a eu une histoire palĂ©obiogĂ©ographique complexe allant de l’hĂ©misphĂšre Sud vers l’hĂ©misphĂšre Nord. Pendant la phase initiale de dispersion Ă  partir du CarbonifĂšre supĂ©rieur jusqu’au Permien infĂ©rieur, ce genre a prospĂ©rĂ© dans un milieu dominĂ© par des eaux froides du Gondwana, suite Ă  la glaciation du PalĂ©ozoĂŻque supĂ©rieur. Les eaux littorales chaudes du Gondwana central et de Laurussia ont Ă©tĂ© colonisĂ©es par Oriocrassatella uniquement durant le Permien infĂ©rieur, parce que ce genre est devenu cosmopolite. Une espĂšce nouvelle, O. piauiensis n. sp., est dĂ©crite de la Formation PiauĂ­ du Pennsylvanien du bassin du ParnaĂ­ba ; elle pourrait reprĂ©senter une premiĂšre adaptation aux eaux chaudes. En outre, et en s’appuyant sur les donnĂ©es disponibles, d’autres espĂšces d’Oriocrassatella se seraient aussi dĂ©finitivement adaptĂ©es Ă  des milieux en eaux chaudes au cours des pĂ©riodes interglaciaires du Pennsylvanien tardif, car des barriĂšres climatiques ont disparu, favorisant des Ă©changes de faune avec dispersion des larves, et migration du sud vers le nord le long des bordures est du Gondwana et de la PalĂ©otĂ©thys.Fil: Anelli, Luiz E.. Universidade de Sao Paulo; BrasilFil: SimĂ”es, Marcello G.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Gonzalez, Carlos Roberto. FundaciĂłn Miguel Lillo; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - TucumĂĄn; ArgentinaFil: Souza, Paulo A.. Universidade Federal do Rio Grande do Sul; Brasi

    Test results of the front-end system for the Silicon Drift Detectors of ALICE

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    The front-end system of the Silicon Drift Detectors (SDDs) of the ALICE experiment is made of two ASICs. The first chip performs the preamplification, temporary analogue storage and analogue-to-digital conversion of the detector signals. The second chip is a digital buffer that allows for a significant reduction of the connection from the front-end module to the outside world. In this paper, the results achieved on the first complete prototype of the front-end system for the SDDs of ALICE are presented

    Molecular complexity of diffuse large B-cell lymphoma: Can it be a roadmap for precision medicine?

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    Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma; it features extreme molecular heterogeneity regardless of the classical cell-of-origin (COO) classification. Despite this, the standard therapeutic approach is still immunochemotherapy (rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone—R-CHOP), which allows a 60% overall survival (OS) rate, but up to 40% of patients experience relapse or refractory (R/R) disease. With the purpose of searching for new clinical parameters and biomarkers helping to make a better DLBCL patient characterization and stratification, in the last years a series of large discovery genomic and transcriptomic studies has been conducted, generating a wealth of information that needs to be put in order. We reviewed these researches, trying ultimately to understand if there are bases offering a roadmap toward personalized and precision medicine also for DLBCL