282 research outputs found

    Strange particle production in proton-proton collisions at s=0.9\sqrt{s}=0.9 TeV with ALICE at the LHC

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    The production of mesons containing strange quarks (Ks0^0_s, ϕ\phi) and both singly and doubly strange baryons (Λ\Lambda, Anti-Λ\Lambda, and Ξ\Xi+Anti-Ξ\Xi) are measured at central rapidity in pp collisions at s\sqrt{s} = 0.9 TeV with the ALICE experiment at the LHC. The results are obtained from the analysis of about 250 k minimum bias events recorded in 2009. Measurements of yields (dN/dy) and transverse momentum spectra at central rapidities for inelastic pp collisions are presented. For mesons, we report yields () of 0.184 ±\pm 0.002 stat. ±\pm 0.006 syst. for Ks0^0_s and 0.021 ±\pm 0.004 stat. ±\pm 0.003 syst. for ϕ\phi. For baryons, we find = 0.048 ±\pm 0.001 stat. ±\pm 0.004 syst. for Λ\Lambda, 0.047 ±\pm 0.002 stat. ±\pm 0.005 syst. for Anti-Λ\Lambda and 0.0101 ±\pm 0.0020 stat. ±\pm 0.0009 syst. for Ξ\Xi+Anti-Ξ\Xi. The results are also compared with predictions for identified particle spectra from QCD-inspired models and provide a baseline for comparisons with both future pp measurements at higher energies and heavy-ion collisions.Comment: 33 pages, 21 captioned figures, 10 tables, authors from page 28, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/387

    Planck intermediate results X : Physics of the hot gas in the Coma cluster

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    Quantum teleportation via a two-qubit Heisenberg XXZ chain-effects of anisotropy and magnetic field

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    We study quantum teleportation via a two-qubit Heisenberg XXZ chain under an inhomogeneous magnetic field. We first consider entanglement teleportation, and then focus on the teleportation fidelity under different conditions. The effects of anisotropy and the magnetic field, both uniform and inhomogeneous, are discussed. We also find that, though entanglement teleportation does require an entangled quantum channel, a nonzero critical value of minimum entanglement is not always necessary

    Planck Intermediate Results II: Comparison of Sunyaev–Zeldovich measurements from Planck and from the Arcminute Microkelvin Imager for 11 galaxy clusters

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    A comparison is presented of Sunyaev–Zeldovich measurements for 11 galaxy clusters as obtained by Planck and by the ground-based interferom- eter, the Arcminute Microkelvin Imager. Assuming a universal spherically-symmetric Generalised Navarro, Frenk & White (GNFW) model for the cluster gas pressure profile, we jointly constrain the integrated Compton-Y parameter (Y500) and the scale radius (θ500) of each cluster. Our resulting constraints in the Y500 − θ500 2D parameter space derived from the two instruments overlap significantly for eight of the clusters, although, overall, there is a tendency for AMI to find the Sunyaev–Zeldovich signal to be smaller in angular size and fainter than Planck. Significant discrepancies exist for the three remaining clusters in the sample, namely A1413, A1914, and the newly-discovered Planck cluster PLCKESZ G139.59+24.18. The robustness of the analysis of both the Planck and AMI data is demonstrated through the use of detailed simulations, which also discount confusion from residual point (radio) sources and from diffuse astrophysical foregrounds as possible explanations for the discrepancies found. For a subset of our cluster sample, we have investigated the dependence of our results on the assumed pressure profile by repeating the analysis adopting the best-fitting GNFW profile shape which best matches X-ray observations. Adopting the best-fitting profile shape from the X-ray data does not, in general, resolve the discrepancies found in this subset of five clusters. Though based on a small sample, our results suggest that the adopted GNFW model may not be sufficiently flexible to describe clusters universally

    Inapplicability of advance directives in a paternalistic setting: the case of a post-communist health system

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    <p>Abstract</p> <p>Background</p> <p>The Albanian medical system and Albanian health legislation have adopted a paternalistic position with regard to individual decision making. This reflects the practices of a not-so-remote past when state-run facilities and a totalitarian philosophy of medical care were politically imposed. Because of this history, advance directives concerning treatment refusal and do-not-resuscitate decisions are still extremely uncommon in Albania. Medical teams cannot abstain from intervening even when the patient explicitly and repeatedly solicits therapeutic abstinence. The Albanian law on health care has no provisions regarding limits or withdrawal of treatment. This restricts the individual's healthcare choices.</p> <p>Discussion</p> <p>The question of <it>'medically futile' </it>interventions and pointless life-prolonging treatment has been discussed by several authors. Dutch physicians call such interventions '<it>medisch zinloos</it>' (<it>senseless</it>), and the Netherlands, as one of the first states to legislate on end-of-life situations, actually regulates such issues through appropriate laws. In contrast, leaving an 'advance directive' is not a viable option for Albanian ailing individuals of advanced age. Verbal requests are provided during periods of mental competence, but unfortunately such instructions are rarely taken seriously, and none of them has ever been upheld in a legal or other official forum.</p> <p>Summary</p> <p>End-of-life decisions, treatment refusal and do-not-resuscitate policies are hazardous options in Albania, from the legal point of view. Complying with them involves significant risk on the part of the physician. Culturally, the application of such instructions is influenced from a mixture of religious beliefs, death coping-behaviors and an immense confusion concerning the role of proxies as decision-makers. Nevertheless, Albanian tradition is familiar with the notion of '<it>amanet</it>', a sort of living will that mainly deals the property and inheritance issues. Such living wills, verbally transmitted, may in certain cases include advance directives regarding end-of-life decisions of the patient including refusal or termination of futile medical treatments. Since these living wills are never formally and legally validated, their application is impossible and treatment refusal remains still non practicable. Tricks to avoid institutional treatment under desperate conditions are used, aiming to provide legal coverage for medical teams and relatives that in extreme situations comply with the advice of withholding senseless treatment.</p

    Higher harmonic anisotropic flow measurements of charged particles in Pb-Pb collisions at 2.76 TeV

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    We report on the first measurement of the triangular v3v_3, quadrangular v4v_4, and pentagonal v5v_5 charged particle flow in Pb-Pb collisions at 2.76 TeV measured with the ALICE detector at the CERN Large Hadron Collider. We show that the triangular flow can be described in terms of the initial spatial anisotropy and its fluctuations, which provides strong constraints on its origin. In the most central events, where the elliptic flow v2v_2 and v3v_3 have similar magnitude, a double peaked structure in the two-particle azimuthal correlations is observed, which is often interpreted as a Mach cone response to fast partons. We show that this structure can be naturally explained from the measured anisotropic flow Fourier coefficients.Comment: 10 pages, 4 figures, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/387

    Practice patterns and 90-day treatment-related morbidity in early-stage cervical cancer

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    To evaluate the impact of the Laparoscopic Approach to Cervical Cancer (LACC) Trial on patterns of care and surgery-related morbidity in early-stage cervical cancer

    Advanced Virgo Plus. Future perspectives

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    While completing the commissioning phase to prepare the Virgo interferometer for the next joint Observation Run (O4), the Virgo collaboration is also finalizing the design of the next upgrades to the detector to be employed in the following Observation Run (O5). The major upgrade will concern decreasing the thermal noise limit, which will imply using very large test masses and increased laser beam size. But this will not be the only upgrade to be implemented in the break between the O4 and O5 observation runs to increase the Virgo detector strain sensitivity. The paper will cover the challenges linked to this upgrade and implications on the detector’s reach and observational potential, reflecting the talk given at 12th Cosmic Ray International Seminar - CRIS 2022 held in September 2022 in Napoli

    Physics of the HL-LHC, and Perspectives at the HE-LHC

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