193 research outputs found

    Roles of Critical Valence Fluctuations in Ce- and Yb-Based Heavy Fermion Metals

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    The roles of critical valence fluctuations of Ce and Yb are discussed as a key origin of several anomalies observed in Ce- and Yb-based heavy fermion systems. Recent development of the theory has revealed that a magnetic field is an efficient control parameter to induce the critical end point of the first-order valence transition. Metamagnetism and non-Fermi liquid behavior caused by this mechanism are discussed by comparing favorably with CeIrIn5, YbAgCu4, and YbIr2Zn20. The interplay of the magnetic order and valence fluctuations offers a key concept for understanding Ce- and Yb-based systems. It is shown that suppression of the magnetic order by enhanced valence fluctuations gives rise to the coincidence of the magnetic-transition point and valence-crossover point at absolute zero as a function of pressure or magnetic field. The interplay is shown to resolve the outstanding puzzle in CeRhIn5 in a unified way. The broader applicability of this newly clarified mechanism is discussed by surveying promising materials such as YbAuCu4, beta-YbAlB4, and YbRh2Si2.Comment: 17 pages, 8 figures, invited paper in special issue on strongly correlated electron system

    New Universality Class of Quantum Criticality in Ce- and Yb-based Heavy Fermions

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    A new universality class of quantum criticality emerging in itinerant electron systems with strong local electron correlations is discussed. The quantum criticality of a Ce- or Yb-valence transition gives us a unified explanation for unconventional criticality commonly observed in heavy fermion metals such as YbRh2Si2 and \beta-YbAlB4, YbCu5-xAlx, and CeIrIn5. The key origin is due to the locality of the critical valence fluctuation mode emerging near the quantum critical end point of the first-order valence transition, which is caused by strong electron correlations for f electrons. Wider relevance of this new criticality and important future measurements to uncover its origin are also discussed.Comment: 20 pages, 4 figure

    Measurement of the mechanical loss of a cooled reflective coating for gravitational wave detection

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    We have measured the mechanical loss of a dielectric multilayer reflective coating (ion-beam sputtered SiO2_2 and Ta2_2O5_5) in cooled mirrors. The loss was nearly independent of the temperature (4 K āˆ¼\sim 300 K), frequency, optical loss, and stress caused by the coating, and the details of the manufacturing processes. The loss angle was (4āˆ¼6)Ɨ10āˆ’4(4 \sim 6) \times 10^{-4}. The temperature independence of this loss implies that the amplitude of the coating thermal noise, which is a severe limit in any precise measurement, is proportional to the square root of the temperature. Sapphire mirrors at 20 K satisfy the requirement concerning the thermal noise of even future interferometric gravitational wave detector projects on the ground, for example, LCGT.Comment: 8 pages, 6 figures, 3 tables : accepted version (by Physical Review D

    Detection of Gamma-rays around 1TeV from RX J0852.0-4622 by CANGAROO-II

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    We have detected gamma-ray emission at the 6sigma level at energies greater than 500GeV from the supernova remnant RX J0852.0-4622 (G266.2-1.2) using the CANGAROO-II Imaging Atmospheric Cherenkov Telescope (IACT). The flux was 0.12 times of that of Crab at 1TeV. The signal centroid is consistent with the peak of the X-ray emission in the north-west rim of the remnant.Comment: 12pages, 4figures, to be published in ApJ

    A Search for TeV Gamma-ray Emission from the PSR B1259-63/SS2883 Binary System with the CANGAROO-II 10-m Telescope

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    Observations of the PSR B1259-63/SS2883 binary system using the CANGAROO-II Cherenkov telescope are reported. This nearby binary consists of a 48msec radio pulsar in a highly eccentric orbit around a Be star, and offers a unique laboratory to investigate the interactions between the outflows of the pulsar and Be star at various distances. It has been pointed out that the relativistic pulsar wind and the dense mass outflow of the Be star may result in the emission of gamma rays up to TeV energies. We have observed the binary in 2000 and 2001, 47 and 157 days after the October 2000 periastron. Upper limits at the 0.13--0.54 Crab level are obtained. A new model calculation for high-energy gamma-ray emission from the Be star outflow is introduced and the estimated gamma-ray flux considering Bremsstrahlung, inverse Compton scattering, and the decay of neutral pions produced in proton-proton interactions, is found to be comparable to the upper limits of these observations. Comparing our results with these model calculations, the mass-outflow parameters of the Be star are constrained.Comment: 29 pages, 10 figures, accepted by Ap

    Selection of antigenically advanced variants of seasonal influenza viruses.

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    Influenza viruses mutate frequently, necessitating constant updates of vaccine viruses. To establish experimental approaches that may complement the current vaccine strain selection process, we selected antigenic variants from human H1N1 and H3N2 influenza virus libraries possessing random mutations in the globular head of the haemagglutinin protein (which includes the antigenic sites) by incubating them with human and/or ferret convalescent sera to human H1N1 and H3N2 viruses. We also selected antigenic escape variants from human viruses treated with convalescent sera and from mice that had been previously immunized against human influenza viruses. Our pilot studies with past influenza viruses identified escape mutants that were antigenically similar to variants that emerged in nature, establishing the feasibility of our approach. Our studies with contemporary human influenza viruses identified escape mutants before they caused an epidemic in 2014-2015. This approach may aid in the prediction of potential antigenic escape variants and the selection of future vaccine candidates before they become widespread in nature.This work was supported by the Bill & Melinda Gates Foundation Global Health Grant OPPGH5383; National Institute of Allergy and Infectious Diseases (NIAID) Public Health Service research grants (USA); ERATO (Japan Science and Technology Agency); the Center for Research on Influenza Pathogenesis (CRIP) funded by the NIAID Contracts HHSN266200700010C and HHSN27 2201400008C; the Japan Initiative for Global Research Network on Infectious Diseases; Grants-in-Aid for Specially Promoted Research from the Ministry of Education, Culture, Sports, Science, and Technology, Japan; Grants-in-Aid from the Ministry of Health, Labour and Welfare, Japan; grants from the Strategic Basic Research Program of the Japan Science and Technology Agency; and by the Advanced Research & Development Programs for Medical Innovation from the Japan Agency for Medical Research and Development (AMED). C.A.R. was supported by a University Research Fellowship from the Royal Society. The authors acknowledge a Netherlands Organisation for Scientific Research (NWO) VICI grant, European Union (EU) FP7 programs EMPERIE (223498) and ANTIGONE (278976); Human Frontier Science Program (HFSP) program grant P0050/2008; Wellcome 087982AIA; and NIH Director's Pioneer Award DP1-OD000490-01. D.F.B and D.J.S. acknowledge CamGrid, the University of Cambridge distributed computer system. The Melbourne WHO Collaborating Centre for Reference and Research on Influenza is supported by the Australian Government Department of Health.This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/nmicrobiol.2016.5

    Effect of a Fatty Acid Additive on the Kinetic Friction and Stiction of Confined Liquid Lubricants

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    Apresentamos neste texto parte das produƧƵes de pesquisa que acompanhou a construĆ§Ć£o de corpos inseridos num Centro de AtenĆ§Ć£o Psicossocial para Ɓlcool e outras Drogas, em cidade do nordeste brasileiro, focando de modo mais acentuado em arranjos de masculinidades. Especial atenĆ§Ć£o Ć© dada Ć  tensĆ£o entre normalizaĆ§Ć£o de corpos e tentativas de (re)existĆŖncias. A argumentaĆ§Ć£o se desenvolve no campo da saĆŗde pĆŗblica, em particular o da saĆŗde mental, e alicerƧada nos estudos de gĆŖnero e sexualidade. A produĆ§Ć£o de dados se valeu de observaƧƵes registradas em diĆ”rio de campo, acompanhamento itinerante, composiĆ§Ć£o de um coletivo de pesquisa, entrevistas, grupos focais em que, dentre outras coisas, se discutia trechos de diĆ”rios de campo, rodas de conversa e oficinas com profissionais e usuĆ”ri*s. A aposta metodolĆ³gica foi a de forjar um modo de narrar coletivo que agenciasse experimentaĆ§Ć£o e desaprendizagens corporais, junto a modos de produzir cuidado em saĆŗde e de fazer pesquisa.Apresentamos neste texto parte das produƧƵes de pesquisa que acompanhou a construĆ§Ć£o de corpos inseridos num Centro de AtenĆ§Ć£o Psicossocial para Ɓlcool e outras Drogas, em cidade do nordeste brasileiro, focando de modo mais acentuado em arranjos de masculinidades. Especial atenĆ§Ć£o Ć© dada Ć  tensĆ£o entre normalizaĆ§Ć£o de corpos e tentativas de (re)existĆŖncias. A argumentaĆ§Ć£o se desenvolve no campo da saĆŗde pĆŗblica, em particular o da saĆŗde mental, e alicerƧada nos estudos de gĆŖnero e sexualidade. A produĆ§Ć£o de dados se valeu de observaƧƵes registradas em diĆ”rio de campo, acompanhamento itinerante, composiĆ§Ć£o de um coletivo de pesquisa, entrevistas, grupos focais em que, dentre outras coisas, se discutia trechos de diĆ”rios de campo, rodas de conversa e oficinas com profissionais e usuĆ”ri*s. A aposta metodolĆ³gica foi a de forjar um modo de narrar coletivo que agenciasse experimentaĆ§Ć£o e desaprendizagens corporais, junto a modos de produzir cuidado em saĆŗde e de fazer pesquisa.Apresentamos neste texto parte das produƧƵes de pesquisa que acompanhou a construĆ§Ć£o de corpos inseridos num Centro de AtenĆ§Ć£o Psicossocial para Ɓlcool e outras Drogas, em cidade do nordeste brasileiro, focando de modo mais acentuado em arranjos de masculinidades. Especial atenĆ§Ć£o Ć© dada Ć  tensĆ£o entre normalizaĆ§Ć£o de corpos e tentativas de (re)existĆŖncias. A argumentaĆ§Ć£o se desenvolve no campo da saĆŗde pĆŗblica, em particular o da saĆŗde mental, e alicerƧada nos estudos de gĆŖnero e sexualidade. A produĆ§Ć£o de dados se valeu de observaƧƵes registradas em diĆ”rio de campo, acompanhamento itinerante, composiĆ§Ć£o de um coletivo de pesquisa, entrevistas, grupos focais em que, dentre outras coisas, se discutia trechos de diĆ”rios de campo, rodas de conversa e oficinas com profissionais e usuĆ”ri*s. A aposta metodolĆ³gica foi a de forjar um modo de narrar coletivo que agenciasse experimentaĆ§Ć£o e desaprendizagens corporais, junto a modos de produzir cuidado em saĆŗde e de fazer pesquisa.Apresentamos neste texto parte das produƧƵes de pesquisa que acompanhou a construĆ§Ć£o de corpos inseridos num Centro de AtenĆ§Ć£o Psicossocial para Ɓlcool e outras Drogas, em cidade do nordeste brasileiro, focando de modo mais acentuado em arranjos de masculinidades. Especial atenĆ§Ć£o Ć© dada Ć  tensĆ£o entre normalizaĆ§Ć£o de corpos e tentativas de (re)existĆŖncias. A argumentaĆ§Ć£o se desenvolve no campo da saĆŗde pĆŗblica, em particular o da saĆŗde mental, e alicerƧada nos estudos de gĆŖnero e sexualidade. A produĆ§Ć£o de dados se valeu de observaƧƵes registradas em diĆ”rio de campo, acompanhamento itinerante, composiĆ§Ć£o de um coletivo de pesquisa, entrevistas, grupos focais em que, dentre outras coisas, se discutia trechos de diĆ”rios de campo, rodas de conversa e oficinas com profissionais e usuĆ”ri*s. A aposta metodolĆ³gica foi a de forjar um modo de narrar coletivo que agenciasse experimentaĆ§Ć£o e desaprendizagens corporais, junto a modos de produzir cuidado em saĆŗde e de fazer pesquisa.Apresentamos neste texto parte das produƧƵes de pesquisa que acompanhou a construĆ§Ć£o de corpos inseridos num Centro de AtenĆ§Ć£o Psicossocial para Ɓlcool e outras Drogas, em cidade do nordeste brasileiro, focando de modo mais acentuado em arranjos de masculinidades. Especial atenĆ§Ć£o Ć© dada Ć  tensĆ£o entre normalizaĆ§Ć£o de corpos e tentativas de (re)existĆŖncias. A argumentaĆ§Ć£o se desenvolve no campo da saĆŗde pĆŗblica, em particular o da saĆŗde mental, e alicerƧada nos estudos de gĆŖnero e sexualidade. A produĆ§Ć£o de dados se valeu de observaƧƵes registradas em diĆ”rio de campo, acompanhamento itinerante, composiĆ§Ć£o de um coletivo de pesquisa, entrevistas, grupos focais em que, dentre outras coisas, se discutia trechos de diĆ”rios de campo, rodas de conversa e oficinas com profissionais e usuĆ”ri*s. A aposta metodolĆ³gica foi a de forjar um modo de narrar coletivo que agenciasse experimentaĆ§Ć£o e desaprendizagens corporais, junto a modos de produzir cuidado em saĆŗde e de fazer pesquisa.Apresentamos neste texto parte das produƧƵes de pesquisa que acompanhou a construĆ§Ć£o de corpos inseridos num Centro de AtenĆ§Ć£o Psicossocial para Ɓlcool e outras Drogas, em cidade do nordeste brasileiro, focando de modo mais acentuado em arranjos de masculinidades. Especial atenĆ§Ć£o Ć© dada Ć  tensĆ£o entre normalizaĆ§Ć£o de corpos e tentativas de (re)existĆŖncias. A argumentaĆ§Ć£o se desenvolve no campo da saĆŗde pĆŗblica, em particular o da saĆŗde mental, e alicerƧada nos estudos de gĆŖnero e sexualidade. A produĆ§Ć£o de dados se valeu de observaƧƵes registradas em diĆ”rio de campo, acompanhamento itinerante, composiĆ§Ć£o de um coletivo de pesquisa, entrevistas, grupos focais em que, dentre outras coisas, se discutia trechos de diĆ”rios de campo, rodas de conversa e oficinas com profissionais e usuĆ”ri*s. A aposta metodolĆ³gica foi a de forjar um modo de narrar coletivo que agenciasse experimentaĆ§Ć£o e desaprendizagens corporais, junto a modos de produzir cuidado em saĆŗde e de fazer pesquisa.The paper presents part of the research productions that accompanied the construction of bodies inserted in a Psychosocial Care Center for Alcohol and Other Drugs (CAPS-AD) of a city in the northern region of Brasil, focusing more sharply on masculinities arrangements. Special attention is given to the tension between normalized bodies and attempts at resistance and (re) exist. The argument is in the field of public health, particularly mental health, and rooted in gender and sexuality studies. The data production methodology made use of observations recorded in a diary, itinerant follow-up of a collective of research, interviews, focus groups where, among other things, was discussed diary topics, conversation circles and workshops. The attempt was to produce a way of collective narrating strategy, combining up experience and body (un)learn well as ways of producing health care and doing research

    Coincidence analysis to search for inspiraling compact binaries using TAMA300 and LISM data

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    Japanese laser interferometric gravitational wave detectors, TAMA300 and LISM, performed a coincident observation during 2001. We perform a coincidence analysis to search for inspiraling compact binaries. The length of data used for the coincidence analysis is 275 hours when both TAMA300 and LISM detectors are operated simultaneously. TAMA300 and LISM data are analyzed by matched filtering, and candidates for gravitational wave events are obtained. If there is a true gravitational wave signal, it should appear in both data of detectors with consistent waveforms characterized by masses of stars, amplitude of the signal, the coalescence time and so on. We introduce a set of coincidence conditions of the parameters, and search for coincident events. This procedure reduces the number of fake events considerably, by a factor āˆ¼10āˆ’4\sim 10^{-4} compared with the number of fake events in single detector analysis. We find that the number of events after imposing the coincidence conditions is consistent with the number of accidental coincidences produced purely by noise. We thus find no evidence of gravitational wave signals. We obtain an upper limit of 0.046 /hours (CL =90= 90 %) to the Galactic event rate within 1kpc from the Earth. The method used in this paper can be applied straightforwardly to the case of coincidence observations with more than two detectors with arbitrary arm directions.Comment: 28 pages, 17 figures, Replaced with the version to be published in Physical Review

    B Chromosomes Have a Functional Effect on Female Sex Determination in Lake Victoria Cichlid Fishes

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    The endemic cichlid fishes in Lake Victoria are a model system for speciation through adaptive radiation. Although the evolution of the sex-determination system may also play a role in speciation, little is known about the sex-determination system of Lake Victoria cichlids. To understand the evolution of the sex-determination system in these fish, we performed cytogenetic analysis in 11 cichlid species from Lake Victoria. B chromosomes, which are present in addition to standard chromosomes, were found at a high prevalence rate (85%) in these cichlids. In one species, B chromosomes were female-specific. Cross-breeding using females with and without the B chromosomes demonstrated that the presence of the B chromosomes leads to a female-biased sex ratio in this species. Although B chromosomes were believed to be selfish genetic elements with little effect on phenotype and to lack protein-coding genes, the present study provides evidence that B chromosomes have a functional effect on female sex determination. FISH analysis using a BAC clone containing B chromosome DNA suggested that the B chromosomes are derived from sex chromosomes. Determination of the nucleotide sequences of this clone (104.5 kb) revealed the presence of several protein-coding genes in the B chromosome, suggesting that B chromosomes have the potential to contain functional genes. Because some sex chromosomes in amphibians and arthropods are thought to be derived from B chromosomes, the B chromosomes in Lake Victoria cichlids may represent an evolutionary transition toward the generation of sex chromosomes
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