245 research outputs found

    Black Hole Chromosphere at the LHC

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    If the scale of quantum gravity is near a TeV, black holes will be copiously produced at the LHC. In this work we study the main properties of the light descendants of these black holes. We show that the emitted partons are closely spaced outside the horizon, and hence they do not fragment into hadrons in vacuum but more likely into a kind of quark-gluon plasma. Consequently, the thermal emission occurs far from the horizon, at a temperature characteristic of the QCD scale. We analyze the energy spectrum of the particles emerging from the "chromosphere", and find that the hard hadronic jets are almost entirely suppressed. They are replaced by an isotropic distribution of soft photons and hadrons, with hundreds of particles in the GeV range. This provides a new distinctive signature for black hole events at LHC.Comment: Incorporates changes made for the version to be published in Phys. Rev. D. Additional details provided on the effect of the chromosphere in cosmic ray shower

    Phenomenology of Randall-Sundrum Black Holes

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    We explore the phenomenology of microscopic black holes in the S1/Z2S^1/Z_2 Randall-Sundrum (RS) model. We consider the canonical framework in which both gauge and matter fields are confined to the brane and only gravity spills into the extra dimension. The model is characterized by two parameters, the mass of the first massive graviton (m1)(m_1), and the curvature 1/1/\ell of the RS anti-de Sitter space. We compute the sensitivity of present and future cosmic ray experiments to various regions of \ell and m1,m_1, and compare with that of Runs I and II at the Tevatron. As part of our phenomenological analysis, we examine constraints placed on \ell by AdS/CFT considerations.Comment: Version to appear in Physical Review D; contains additional analysis on sensitivity of OW

    Black Holes from Cosmic Rays: Probes of Extra Dimensions and New Limits on TeV-Scale Gravity

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    If extra spacetime dimensions and low-scale gravity exist, black holes will be produced in observable collisions of elementary particles. For the next several years, ultra-high energy cosmic rays provide the most promising window on this phenomenon. In particular, cosmic neutrinos can produce black holes deep in the Earth's atmosphere, leading to quasi-horizontal giant air showers. We determine the sensitivity of cosmic ray detectors to black hole production and compare the results to other probes of extra dimensions. With n \ge 4 extra dimensions, current bounds on deeply penetrating showers from AGASA already provide the most stringent bound on low-scale gravity, requiring a fundamental Planck scale M_D > 1.3 - 1.8 TeV. The Auger Observatory will probe M_D as large as 4 TeV and may observe on the order of a hundred black holes in 5 years. We also consider the implications of angular momentum and possible exponentially suppressed parton cross sections; including these effects, large black hole rates are still possible. Finally, we demonstrate that even if only a few black hole events are observed, a standard model interpretation may be excluded by comparison with Earth-skimming neutrino rates.Comment: 30 pages, 18 figures; v2: discussion of gravitational infall, AGASA and Fly's Eye comparison added; v3: Earth-skimming results modified and strengthened, published versio

    Acceptability of multipurpose human papillomavirus vaccines among providers and mothers of adolescent girls: A mixed-methods study in five countries

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    Introduction Multipurpose vaccines (MPVs) could be formulated to prevent multiple sexually transmitted infections simultaneously. Little is known about acceptability of MPVs among vaccine health care providers (HCPs) or mothers of adolescent girls. Methods 151 adolescent vaccine providers and 118 mothers of adolescent girls aged 9–14 were recruited from five geographically-diverse countries: Argentina, Malaysia, South Africa, South Korea, and Spain. We assessed providers’ preferences for single-purpose human papillomavirus (HPV) vaccine versus MPVs (including HPV+herpes simplex virus (HSV)−2, HPV+HIV, or HPV+HSV-2+HIV) via quantitative surveys. Maternal MPV attitudes were assessed in four focus group discussions (FGDs) in each country. Results Most providers preferred MPVs over single-purpose HPV vaccination, with preference ranging from 61% in Malaysia to 96% in South Africa. HPV+HSV-2+HIV was the most preferred MPV formulation (56–82%). Overall, 53% of the mothers preferred MPVs over single-purpose HPV vaccines, with strongest support in South Africa (90%) and lowest support in South Korea (29%). Convenience and trust in the health care system were commonly-cited reasons for MPV acceptability. Safety and efficacy concerns were common barriers to accepting MPVs, though specific concerns differed by country. Across FGDs, additional safety and efficacy information on MPVs were requested, particularly from trusted sources like HCPs. Conclusions Though maternal acceptability of MPVs varied by country, MPV acceptability would be enhanced by having HCPs provide parents with additional MPV vaccine safety and efficacy information. While most providers preferred MPVs, future health behavior research should identify acceptability barriers, and targeted provider interventions should equip providers to improve vaccination discussions with parents

    The level of blood plasma mitochondrial DNA upon acute myocardium damage in experiment

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    The aim of the present investigation is to study the level of plasma mtDNA as a potential marker of cardiomyocyte damage in 2 and 4 h after subcutaneous injection of adrenaline and during the formed morphological alterations of the myocardium (3 days). Methods. Real time PCR. Male Wistar rats were used as the experimental animals. Results. It was shown that during the increase in the activity of cytolysis biomarkers, at the first hours after adrenaline injection, no reliable increase is observed in the level of free circulating blood mtDNA. A tendency of 2.5-fold increase in this parameter was established at the third day after adrenaline injection during the development of acute inflammatory process in the myocardium. On the whole, further researches are needed on the dynamics of mtDNA level upon acute damage of the myocardium in experimental and clinical investigations for unbiased estimation of the prospects of using the parameter in laboratory diagnostics. Keywords: mitochondrial DNA, cardiovascular diseases, adrenaline myocarditis, cytolysis biomarkers.Цель. Изучить уровень мтДНК плазмы крови как возможного маркера повреждений кардиомиоцитов через 2 и 4 ч после подкожной инъекции адреналина и на фоне сформированных морфологических изменений миокарда (3-и сут). Методы. Полимеразная цепная реакция в реальном времени. В экспериментах использовали самцов крыс линии Вистар. Результаты. Показано, что наряду с увеличением активности биомаркеров цитолиза в первые часы после введения адреналина значимого повышения уровня свободно циркулирующей мтДНК крови не происходит. Установлена тенденция к 2,5-кратному возрастанию данного показателя на 3-и сут после инъекции адреналина на фоне развития острого воспалительного процесса в миокарде. Выводы. В целом для объективной оценки перспектив этого показателя в лабораторной диагностике инфаркта миокарда необходимо дальнейшее изучение динамики уровня мтДНК при острых повреждениях миокарда в экспериментальных и клинических исследованиях. Ключевые слова: митохондриальная ДНК, сердечно-сосудистые заболевания, адреналиновый миокардит, биомаркеры цитолиза.Мета. Вивчити рівень мтДНК плазми крові як можливого маркера пошкоджень кардіоміоцитиів через 2 і 4 год після підшкірної ін’єкції адреналіну та на фоні сформованих морфологічних змін міокарда (3-тя доба). Методи. Полімеразна ланцюгова реакція у реальному часі. В експериментах використано самців щурів лінії Вістар. Результати. Показано, що поряд із збільшенням активності біомаркерів цитолізу в перші години після введення адреналіну суттєвого підвищення рівня вільно циркулюючої мтДНК крові не відбувається. Встановлено тенденцію до 2,5-разового зростання даного показника на 3-тю добу після ін’кції адреналіну на фоні розвитку гострого запального процесу в міокарді. Висновки. У цілому для об’єктивної оцінки перспектив цього показника у лабораторній діагностиці інфаркта міокарда необхідно подальше вивчення динаміки рівня мтДНК при гострих ураженнях міокарда в експериментальних і клінічних дослідженнях. Ключові слова: мітохондріальна ДНК, серцево-судинні захворювання, адреналіновий міокардит, біомаркери цитолізу

    Results of Prevention of REStenosis with Tranilast and its Outcomes (PRESTO) trial

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    BACKGROUND: Restenosis after percutaneous coronary intervention (PCI) is a major problem affecting 15% to 30% of patients after stent placement. No oral agent has shown a beneficial effect on restenosis or on associated major adverse cardiovascular events. In limited trials, the oral agent tranilast has been shown to decrease the frequency of angiographic restenosis after PCI. METHODS AND RESULTS: In this double-blind, randomized, placebo-controlled trial of tranilast (300 and 450 mg BID for 1 or 3 months), 11 484 patients were enrolled. Enrollment and drug were initiated within 4 hours after successful PCI of at least 1 vessel. The primary end point was the first occurrence of death, myocardial infarction, or ischemia-driven target vessel revascularization within 9 months and was 15.8% in the placebo group and 15.5% to 16.1% in the tranilast groups (P=0.77 to 0.81). Myocardial infarction was the only component of major adverse cardiovascular events to show some evidence of a reduction with tranilast (450 mg BID for 3 months): 1.1% versus 1.8% with placebo (P=0.061 for intent-to-treat population). The primary reason for not completing treatment was > or =1 hepatic laboratory test abnormality (11.4% versus 0.2% with placebo, P<0.01). In the angiographic substudy composed of 2018 patients, minimal lumen diameter (MLD) was measured by quantitative coronary angiography. At follow-up, MLD was 1.76+/-0.77 mm in the placebo group, which was not different from MLD in the tranilast groups (1.72 to 1.78+/-0.76 to 80 mm, P=0.49 to 0.89). In a subset of these patients (n=1107), intravascular ultrasound was performed at follow-up. Plaque volume was not different between the placebo and tranilast groups (39.3 versus 37.5 to 46.1 mm(3), respectively; P=0.16 to 0.72). CONCLUSIONS: Tranilast does not improve the quantitative measures of restenosis (angiographic and intravascular ultrasound) or its clinical sequelae

    Study of the B^0 Semileptonic Decay Spectrum at the Upsilon(4S) Resonance

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    We have made a first measurement of the lepton momentum spectrum in a sample of events enriched in neutral B's through a partial reconstruction of B0 --> D*- l+ nu. This spectrum, measured with 2.38 fb**-1 of data collected at the Upsilon(4S) resonance by the CLEO II detector, is compared directly to the inclusive lepton spectrum from all Upsilon(4S) events in the same data set. These two spectra are consistent with having the same shape above 1.5 GeV/c. From the two spectra and two other CLEO measurements, we obtain the B0 and B+ semileptonic branching fractions, b0 and b+, their ratio, and the production ratio f+-/f00 of B+ and B0 pairs at the Upsilon(4S). We report b+/b0=0.950 (+0.117-0.080) +- 0.091, b0 = (10.78 +- 0.60 +- 0.69)%, and b+ = (10.25 +- 0.57 +- 0.65)%. b+/b0 is equivalent to the ratio of charged to neutral B lifetimes, tau+/tau0.Comment: 14 page, postscript file also available at http://w4.lns.cornell.edu/public/CLN

    Measurement of the Mass Splittings between the bbˉχb,J(1P)b\bar{b}\chi_{b,J}(1P) States

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    We present new measurements of photon energies and branching fractions for the radiative transitions: Upsilon(2S)->gamma+chi_b(J=0,1,2). The masses of the chi_b states are determined from the measured radiative photon energies. The ratio of mass splittings between the chi_b substates, r==(M[J=2]-M[J=1])/(M[J=1]-M[J=0]) with M the chi_b mass, provides information on the nature of the bbbar confining potential. We find r(1P)=0.54+/-0.02+/-0.02. This value is in conflict with the previous world average, but more consistent with the theoretical expectation that r(1P)<r(2P); i.e., that this mass splittings ratio is smaller for the chi_b(1P) triplet than for the chi_b(2P) triplet.Comment: 11 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Radiative Decay Modes of the D0D^{0} Meson

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    Using data recorded by the CLEO-II detector at CESR we have searched for four radiative decay modes of the D0D^0 meson: D0ϕγD^0\to\phi\gamma, D0ωγD^0\to\omega\gamma, D0KˉγD^0\to\bar{K}^{*}\gamma, and D0ρ0γD^0\to\rho^0\gamma. We obtain 90% CL upper limits on the branching ratios of these modes of 1.9×1041.9\times 10^{-4}, 2.4×1042.4\times 10^{-4}, 7.6×1047.6\times 10^{-4} and 2.4×1042.4\times 10^{-4} respectively.Comment: 15 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Black Holes at the LHC

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    In these two lectures, we will address the topic of the creation of small black holes during particle collisions in a ground-based accelerator, such as LHC, in the context of a higher-dimensional theory. We will cover the main assumptions, criteria and estimates for their creation, and we will discuss their properties after their formation. The most important observable effect associated with their creation is likely to be the emission of Hawking radiation during their evaporation process. After presenting the mathematical formalism for its study, we will review the current results for the emission of particles both on the brane and in the bulk. We will finish with a discussion of the methodology that will be used to study these spectra, and the observable signatures that will help us identify the black-hole events.Comment: 37 pages, 14 figures, lectures presented in the 4th Aegean Summer School on Black Holes, 17-22 September 2007, Lesvos, Greece, typos corrected, comments and references adde
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