66 research outputs found

    Activities of \gamma-ray emitting isotopes in rainwater from Greater Sudbury, Canada following the Fukushima incident

    Full text link
    We report the activity measured in rainwater samples collected in the Greater Sudbury area of eastern Canada on 3, 16, 20, and 26 April 2011. The samples were gamma-ray counted in a germanium detector and the isotopes 131I and 137Cs, produced by the fission of 235U, and 134Cs, produced by neutron capture on 133Cs, were observed at elevated levels compared to a reference sample of ice-water. These elevated activities are ascribed to the accident at the Fukushima Dai-ichi nuclear reactor complex in Japan that followed the 11 March earthquake and tsunami. The activity levels observed at no time presented health concerns.Comment: 4 pages, 8 figure

    Refractive index sensing setup based on a taper and an intrinsic micro Fabry-Perot interferometer

    Get PDF
    In this work, a refractive index sensor setup based on a biconically tapered fiber (BTF) concatenated to an intrinsic all-fiber micro Fabry-Perot interferometer (MFPI) is presented. Here, the power of the MFPI spectral fringes decreases as the refractive index interacts with theevanescent field of the BTF segment. Furthermore, it is demonstrated that the RI sensitivity can be enhanced by bending the BTF segment.Finally, it is shown that by using this sensing arrangement, at ~1.53 µm wavelength, it is possible to detect refractive index changeswithin the measurement range of 1.3 to 1.7 RIU, with a sensitivity of 39.92 dB/RIU and a RI resolution of 2.5 x 10^-3 RIU with a curvature of C = 18.02 m^-1

    Improving Photoelectron Counting and Particle Identification in Scintillation Detectors with Bayesian Techniques

    Full text link
    Many current and future dark matter and neutrino detectors are designed to measure scintillation light with a large array of photomultiplier tubes (PMTs). The energy resolution and particle identification capabilities of these detectors depend in part on the ability to accurately identify individual photoelectrons in PMT waveforms despite large variability in pulse amplitudes and pulse pileup. We describe a Bayesian technique that can identify the times of individual photoelectrons in a sampled PMT waveform without deconvolution, even when pileup is present. To demonstrate the technique, we apply it to the general problem of particle identification in single-phase liquid argon dark matter detectors. Using the output of the Bayesian photoelectron counting algorithm described in this paper, we construct several test statistics for rejection of backgrounds for dark matter searches in argon. Compared to simpler methods based on either observed charge or peak finding, the photoelectron counting technique improves both energy resolution and particle identification of low energy events in calibration data from the DEAP-1 detector and simulation of the larger MiniCLEAN dark matter detector.Comment: 16 pages, 16 figure

    First observation of a narrow charm-strange meson DsJ(2632) -> Ds eta and D0 K+

    Full text link
    We report the first observation of a charm-strange meson DsJ(2632) at a mass of 2632.6+/-1.6 MeV/c^2 in data from SELEX, the charm hadro-production experiment E781 at Fermilab. This state is seen in two decay modes, Ds eta and D0 K+. In the Ds eta decay mode we observe an excess of 49.3 events with a significance of 7.2sigma at a mass of 2635.9+/-2.9 MeV/c^2. There is a corresponding peak of 14 events with a significance of 5.3sigma at 2631.5+/-1.9 MeV/c^2 in the decay mode D0 K+. The decay width of this state is <17 MeV/c^2 at 90% confidence level. The relative branching ratio Gamma(D0K+)/Gamma(Dseta) is 0.16+/-0.06. The mechanism which keeps this state narrow is unclear. Its decay pattern is also unusual, being dominated by the Ds eta decay mode.Comment: 5 pages, 3 included eps figures. v2 as accepted for publication by PR

    Search for invisible modes of nucleon decay in water with the SNO+ detector

    Get PDF
    This paper reports results from a search for nucleon decay through invisible modes, where no visible energy is directly deposited during the decay itself, during the initial water phase of SNO+. However, such decays within the oxygen nucleus would produce an excited daughter that would subsequently deexcite, often emitting detectable gamma rays. A search for such gamma rays yields limits of 2.5×1029  y at 90% Bayesian credibility level (with a prior uniform in rate) for the partial lifetime of the neutron, and 3.6×1029  y for the partial lifetime of the proton, the latter a 70% improvement on the previous limit from SNO. We also present partial lifetime limits for invisible dinucleon modes of 1.3×1028  y for nn, 2.6×1028  y for pn and 4.7×1028  y for pp, an improvement over existing limits by close to 3 orders of magnitude for the latter two

    Observation of Antineutrinos from Distant Reactors using Pure Water at SNO+

    Full text link
    The SNO+ collaboration reports the first observation of reactor antineutrinos in a Cherenkov detector. The nearest nuclear reactors are located 240 km away in Ontario, Canada. This analysis used events with energies lower than in any previous analysis with a large water Cherenkov detector. Two analytical methods were used to distinguish reactor antineutrinos from background events in 190 days of data and yielded consistent observations of antineutrinos with a combined significance of 3.5 σ\sigma.Comment: v2: add missing author, add link to supplemental materia

    The transverse momentum dependence of charged kaon Bose-Einstein correlations in the SELEX experiment

    Get PDF
    CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOWe report the measurement of the one-dimensional charged kaon correlation functions using 600GeV/c σ-, π- and 540GeV/c p beams from the SELEX (E781) experiment at the Fermilab Tevatron. K±K± correlation functions are studied for three transverse pair momentum, kT, ranges and parameterized by a Gaussian form. The emission source radii, R, and the correlation strength, λ, are extracted. The analysis shows a decrease of the source radii with increasing kaon transverse pair momentum for all beam types. © 2015 The Authors.We report the measurement of the one-dimensional charged kaon correlation functions using 600GeV/c σ-, π- and 540GeV/c p beams from the SELEX (E781) experiment at the Fermilab Tevatron. K±K± correlation functions are studied for three transverse pair momentum, kT, ranges and parameterized by a Gaussian form. The emission source radii, R, and the correlation strength, λ, are extracted. The analysis shows a decrease of the source radii with increasing kaon transverse pair momentum for all beam types.753458464CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOSem informaçãoSem informaçãoRuss, J.S., Akchurin, N., Andreev, V.A., First charm hadroproduction results from SELEX (1998) ICHEP'98 Proc. Int. Conf. on High Energy Physics II, p. 1259. , arxiv:hep-ex/9812031Goldhaber, G., Fowler, W.B., Goldhaber, S., Hoang, T.F., Kalogeropoulos, T.E., Powell, W.M., Pion-pion correlations in antiproton annihilation events (1959) Phys. Rev. Lett., 3, pp. 181-183Goldhaber, G., Goldhaber, S., Lee, W., Pais, A., Influence of Bose-Einstein statistics on the antiproton-proton annihilation process (1960) Phys. Rev., 120, pp. 300-312Kopylov, G.I., Podgoretsky, M.I., Correlations of identical particles emitted by highly excited nuclei (1972) Sov. J. Nucl. Phys., 15, pp. 219-223Kopylov, G.I., Podgoretsky, M.I., Multiple production and interference of particles emitted by moving sources (1974) Sov. J. Nucl. Phys., 18, pp. 336-341Kopylov, G.I., Like particle correlations as a tool to study the multiple production mechanism (1974) Phys. Lett. B, 50, pp. 472-474Abbiendi, G., Transverse and longitudinal Bose-Einstein correlations in hadronic Z0 decays (2000) Eur. Phys. J. C, 16, pp. 423-433. , arxiv:hep-ex/0002062Chekanov, S., Bose-Einstein correlations in one and two dimensions in deep inelastic scattering (2004) Phys. Lett. B, 583, pp. 231-246. , arxiv:hep-ex/0311030Aamodt, K., Two-pion Bose-Einstein correlations in pp collisions at s=900GeV (2010) Phys. Rev. D, 82. , arxiv:1007.0516Beker, H., MT dependence of boson interferometry in heavy ion collisions at the CERN SPS (1995) Phys. Rev. Lett., 74, pp. 3340-3343Adamczyk, L., Beam-energy-dependent two-pion interferometry and the freeze-out eccentricity of pions measured in heavy ion collisions at the STAR detector (2015) Phys. Rev. C, 92. , arxiv:1403.4972Adams, J., Experimental and theoretical challenges in the search for the quark-gluon plasma: the STAR Collaboration's critical assessment of the evidence from RHIC collisions (2005) Nucl. Phys. A, 757, pp. 102-183. , arxiv:nucl-ex/0501009Adcox, K., Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: experimental evaluation by the PHENIX Collaboration (2005) Nucl. Phys. A, 757, pp. 184-283. , arxiv:nucl-ex/0410003Back, B.B., The PHOBOS perspective on discoveries at RHIC (2005) Nucl. Phys. A, 757, pp. 28-101. , arxiv:nucl-ex/0410022Arsene, I., Quark-gluon plasma and color glass condensate at RHIC? The perspective from the BRAHMS experiment (2005) Nucl. Phys. A, 757, pp. 1-27. , arxiv:nucl-ex/0410020Akkelin, S.V., Sinyukov, Y.M., The HBT-interferometry of expanding sources (1995) Phys. Lett. B, 356, pp. 525-530Alexander, G., Cohen, I., Levin, E., The dependence of the emission size on the hadron mass (1999) Phys. Lett. B, 452, pp. 159-166. , arxiv:hep-ph/9901341Kittel, W., Bose-Einstein correlations in Z fragmentation and other reactions (2001) Acta Phys. Pol. B, 32, pp. 3927-3972. , arxiv:hep-ph/0110088Chajȩcki, Z., Femtoscopy in hadron and lepton collisions: RHIC results and world systematics (2009) Acta Phys. Pol. B, 40, pp. 1119-1136. , arxiv:0901.4078Aggarwal, M.M., Pion femtoscopy in p+p collisions at s=200GeV (2011) Phys. Rev. C, 83. , arxiv:1004.0925Engelfried, J., The SELEX phototube RICH detector (1999) Nucl. Instrum. Methods A, 431, pp. 53-69. , arxiv:hep-ex/9811001Engelfried, J., The E781 (SELEX) RICH detector (1998) Nucl. Instrum. Methods A, 409, pp. 439-442Sjöstrand, T., Mrenna, S., Skands, P., PYTHIA 6.4 physics and manual (2006) J. High Energy Phys., 5. , arxiv:hep-ph/0603175v2Chajȩcki, Z., Lisa, M., Global conservation laws and femtoscopy of small systems (2008) Phys. Rev. C, 78. , arxiv:0803.0022Lednický, R., Lyuboshitz, V.L., Erazmus, B., Nouais, D., How to measure which sort of particles was emitted earlier and which later (1996) Phys. Lett. B, 373, pp. 30-34Voloshin, S., Lednický, R., Panitkin, S., Xu, N., Relative space-time asymmetries in pion and nucleon production in noncentral nucleus-nucleus collisions at high-energies (1997) Phys. Rev. Lett., 79, pp. 4766-4769. , arxiv:nucl-th/9708044Pratt, S., Shapes and sizes from non-identical-particle correlations (2007) Braz. J. Phys., 37, pp. 871-876. , arxiv:nucl-th/0612006Lednický, R., Finite-size effect on two-particle production (2008) J. Phys. G, Nucl. Part. Phys., 35Lednický, R., Lyuboshitz, V.V., Lyuboshitz, V.L., Final-state interactions in multichannel quantum systems and pair correlations of nonidentical and identical particles at low relative velocities (1998) Phys. At. Nucl., 61, pp. 2050-2063Bowler, M.G., Coulomb corrections to Bose-Einstein corrections have greatly exaggerated (1991) Phys. Lett. B, 270, pp. 69-74Sinyukov, Y., Lednický, R., Akkelin, S.V., Pluta, J., Erazmus, B., Coulomb corrections to Bose-Einstein corrections have greatly exaggerated (1998) Phys. Lett. B, 432, pp. 248-257Adams, J., Pion interferometry in Au+Au collisions at sNN=200GeV (2005) Phys. Rev. C, 71. , arxiv:nucl-ex/0411036Skands, P.Z., Tuning Monte Carlo generators: the Perugia tunes (2010) Phys. Rev. D, 82. , arxiv:1005.3457Abelev, B., Charged kaon femtoscopic correlations in pp collisions at s=7TeV (2013) Phys. Rev. D, 87. , arxiv:1212.5958v2Khachatryan, V., Measurement of Bose-Einstein correlations in pp collisions at s = 0.9 and 7 TeV (2011) J. High Energy Phys., 5. , arxiv:1101.3518Akkelin, S.V., Sinyukov, Y.M., Deciphering nonfemtoscopic two-pion correlations in p+p collisions with simple analytical models (2012) Phys. Rev. D, 85. , arxiv:1106.5120Lednický, R., Progulova, T.B., Influence of resonances on Bose-Einstein correlations of identical pions (1992) Z. Phys. C, 55, pp. 295-305Lisa, M., Pratt, S., Soltz, R., Wiedemann, U., Femtoscopy in relativistic heavy ion collisions: two decades of progress (2005) Annu. Rev. Nucl. Part. Sci., 55, pp. 357-402. , arxiv:nucl-ex/0505014Pratt, S., Pion interferometry for exploding sources (1984) Phys. Rev. Lett., 53, pp. 1219-1221Abbiendi, G., Bose-Einstein study of position-momentum correlations of charged pions in hadronic Z0 decays (2007) Eur. Phys. J. C, 52, pp. 787-803. , arxiv:0708.1122Achard, P., Test of the τ-model of Bose-Einstein correlations and reconstruction of the source function in hadronic Z-boson decay at LEP (2011) Eur. Phys. J. C, 71, p. 1648. , arxiv:1105.4788Aamodt, K., Femtoscopy of pp collisions at s = 0.9 and 7 TeV at the LHC with two-pion Bose-Einstein correlations (2011) Phys. Rev. D, 84. , arxiv:1101.3665Wiedemann, U.A., Heinz, U.W., Resonance contributions to Hanbury-Brown-Twiss correlation radii (1997) Phys. Rev. C, 56, pp. 3265-3286. , arxiv:nucl-th/9611031Werner, K., Karpenko, I., Pierog, T., Bleicher, M., Mikhailov, K., Evidence for hydrodynamic evolution in proton-proton scattering at 900 GeV (2011) Phys. Rev. C, 83. , arxiv:1010.0400Humanic, T.J., Predictions for two-pion correlations for s=14TeV proton-proton collisions (2007) Phys. Rev. C, 76. , arxiv:nucl-th/0612098Alexopoulos, T., Study of source size in pp- collisions at s=1.8TeV using pion interferometry (1993) Phys. Rev. D, 48, pp. 1931-1942Csorgo, T., Kittel, W., Metzger, W.J., Novák, T., Parametrization of Bose-Einstein correlations and reconstruction of the space-time evolution of pion production in e+e- annihilation (2008) Phys. Lett. B, 663, pp. 214-216. , arxiv:0803.3528Bialas, A., Kucharczyk, M., Palka, H., Zalewski, K., Mass dependence of HBT correlations in e+e- annihilation (2000) Phys. Rev. D, 62. , arxiv:hep-ph/0006290Alexander, G., Open questions related to Bose-Einstein correlations in e+e- → hadrons (2004) Acta Phys. Pol. B, 35, pp. 69-76. , arxiv:hep-ph/0311114Alexander, G., Mass and transverse mass effects on the hadron emitter size (2001) Phys. Lett. B, 506, pp. 45-51. , arxiv:hep-ph/0101319The authors are indebted to the staff of Fermi National Accelerator Laboratory and for invaluable technical support from the staffs of collaborating institutions. This project was supported in part by Bundesministerium für Bildung, Wissenschaft, Forschung und Technologie, Consejo Nacional de Ciencia y Tecnología (CONACyT), Conselho Nacional de Desenvolvimento Científico e Tecnológico, Fondo de Apoyo a la Investigación (UASLP), Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), the Israel Science Foundation founded by the Israel Academy of Sciences and Humanities, Istituto Nazionale di Fisica Nucleare (INFN), the International Science Foundation (ISF), the National Science Foundation, NATO, the Russian Academy of Sciences, the Russian Ministry of Science and Technology, the Russian Foundation for Basic Research (research project No. 11-02-01302-a), the Secretaría de Educación Pública (Mexico), the Turkish Scientific and Technological Research Board (TÜBİTAK), and the U.S. Department of Energy. We thank ITEP and National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) for providing computing powers and support for data analysis and simulations. The authors also would like to thank Prof. Michael Lisa and Prof. Richard Lednický for helpful comments and fruitful discussions

    Bezlotoxumab for Prevention of Recurrent Clostridium difficile Infection

    No full text
    BACKGROUND Clostridium difficile is the most common cause of infectious diarrhea in hospitalized patients. Recurrences are common after antibiotic therapy. Actoxumab and bezlotoxumab are human monoclonal antibodies against C. difficile toxins A and B, respectively. METHODS We conducted two double-blind, randomized, placebo-controlled, phase 3 trials, MODIFY I and MODIFY II, involving 2655 adults receiving oral standard-of-care antibiotics for primary or recurrent C. difficile infection. Participants received an infusion of bezlotoxumab (10 mg per kilogram of body weight), actoxumab plus bezlotoxumab (10 mg per kilogram each), or placebo; actoxumab alone (10 mg per kilogram) was given in MODIFY I but discontinued after a planned interim analysis. The primary end point was recurrent infection (new episode after initial clinical cure) within 12 weeks after infusion in the modified intention-to-treat population. RESULTS In both trials, the rate of recurrent C. difficile infection was significantly lower with bezlotoxumab alone than with placebo (MODIFY I: 17% [67 of 386] vs. 28% [109 of 395]; adjusted difference, −10.1 percentage points; 95% confidence interval [CI], −15.9 to −4.3; P<0.001; MODIFY II: 16% [62 of 395] vs. 26% [97 of 378]; adjusted difference, −9.9 percentage points; 95% CI, −15.5 to −4.3; P<0.001) and was significantly lower with actoxumab plus bezlotoxumab than with placebo (MODIFY I: 16% [61 of 383] vs. 28% [109 of 395]; adjusted difference, −11.6 percentage points; 95% CI, −17.4 to −5.9; P<0.001; MODIFY II: 15% [58 of 390] vs. 26% [97 of 378]; adjusted difference, −10.7 percentage points; 95% CI, −16.4 to −5.1; P<0.001). In prespecified subgroup analyses (combined data set), rates of recurrent infection were lower in both groups that received bezlotoxumab than in the placebo group in subpopulations at high risk for recurrent infection or for an adverse outcome. The rates of initial clinical cure were 80% with bezlotoxumab alone, 73% with actoxumab plus bezlotoxumab, and 80% with placebo; the rates of sustained cure (initial clinical cure without recurrent infection in 12 weeks) were 64%, 58%, and 54%, respectively. The rates of adverse events were similar among these groups; the most common events were diarrhea and nausea. CONCLUSIONS Among participants receiving antibiotic treatment for primary or recurrent C. difficile infection, bezlotoxumab was associated with a substantially lower rate of recurrent infection than placebo and had a safety profile similar to that of placebo. The addition of actoxumab did not improve efficacy. (Funded by Merck; MODIFY I and MODIFY II ClinicalTrials.gov numbers, NCT01241552 and NCT01513239.

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

    Get PDF
    Background: Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. // Methods: We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. // Findings: We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. // Interpretation: Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030
    corecore