1,596 research outputs found

    Shear modulus of the hadron-quark mixed phase

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    Robust arguments predict that a hadron-quark mixed phase may exist in the cores of some "neutron" stars. Such a phase forms a crystalline lattice with a shear modulus higher than that of the crust due to the high density and charge separation, even allowing for the effects of charge screening. This may lead to strong continuous gravitational-wave emission from rapidly rotating neutron stars and gravitational-wave bursts associated with magnetar flares and pulsar glitches. We present the first detailed calculation of the shear modulus of the mixed phase. We describe the quark phase using the bag model plus first-order quantum chromodynamics corrections and the hadronic phase using relativistic mean-field models with parameters allowed by the most massive pulsar. Most of the calculation involves treating the "pasta phases" of the lattice via dimensional continuation, and we give a general method for computing dimensionally continued lattice sums including the Debye model of charge screening. We compute all the shear components of the elastic modulus tensor and angle average them to obtain the effective (scalar) shear modulus for the case where the mixed phase is a polycrystal. We include the contributions from changing the cell size, which are necessary for the stability of the lower-dimensional portions of the lattice. Stability also requires a minimum surface tension, generally tens of MeV/fm^2 depending on the equation of state. We find that the shear modulus can be a few times 10^33 erg/cm^3, two orders of magnitude higher than the first estimate, over a significant fraction of the maximum mass stable star for certain parameter choices.Comment: 22 pages, 12 figures, version accepted by Phys. Rev. D, with the corrections to the shear modulus computation and Table I given in the erratu

    Gender Differences in Russian Colour Naming

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    In the present study we explored Russian colour naming in a web-based psycholinguistic experiment (http://www.colournaming.com). Colour singletons representing the Munsell Color Solid (N=600 in total) were presented on a computer monitor and named using an unconstrained colour-naming method. Respondents were Russian speakers (N=713). For gender-split equal-size samples (NF=333, NM=333) we estimated and compared (i) location of centroids of 12 Russian basic colour terms (BCTs); (ii) the number of words in colour descriptors; (iii) occurrences of BCTs most frequent non-BCTs. We found a close correspondence between females’ and males’ BCT centroids. Among individual BCTs, the highest inter-gender agreement was for seryj ‘grey’ and goluboj ‘light blue’, while the lowest was for sinij ‘dark blue’ and krasnyj ‘red’. Females revealed a significantly richer repertory of distinct colour descriptors, with great variety of monolexemic non-BCTs and “fancy” colour names; in comparison, males offered relatively more BCTs or their compounds. Along with these measures, we gauged denotata of most frequent CTs, reflected by linguistic segmentation of colour space, by employing a synthetic observer trained by gender-specific responses. This psycholinguistic representation revealed females’ more refined linguistic segmentation, compared to males, with higher linguistic density predominantly along the redgreen axis of colour space

    ASAS-SN follow-up of IceCube high-energy neutrino alerts

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    We report on the search for optical counterparts to IceCube neutrino alerts released between April 2016 and August 2021 with the All-Sky Automated Survey for SuperNovae (ASAS-SN). Despite the discovery of a diffuse astrophysical high-energy neutrino flux in 2013, the source of those neutrinos remains largely unknown. Since 2016, IceCube has published likely-astrophysical neutrinos as public realtime alerts. Through a combination of normal survey and triggered target-of-opportunity observations, ASAS-SN obtained images within 1 hour of the neutrino detection for 20% (11) of all observable IceCube alerts and within one day for another 57% (32). For all observable alerts, we obtained images within at least two weeks from the neutrino alert. ASAS-SN provides the only optical follow-up for about 17% of IceCube's neutrino alerts. We recover the two previously claimed counterparts to neutrino alerts, the flaring-blazar TXS 0506+056 and the tidal disruption event AT2019dsg. We investigate the light curves of previously-detected transients in the alert footprints, but do not identify any further candidate neutrino sources. We also analysed the optical light curves of Fermi 4FGL sources coincident with high-energy neutrino alerts, but do not identify any contemporaneous flaring activity. Finally, we derive constraints on the luminosity functions of neutrino sources for a range of assumed evolution models

    Establishment of a community managed marine reserve in the Bay of Ranobe, southwest Madagascar

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    The Bay of Ranobe, in southwest Madagascar, once noted for its high biodiversity and fish abundance, is under increasing pressure from overfishing, pollution, sedimentation and tourism. The declining health of the coral reef is reflected in fishery productivity and survey data on biological diversity. Sustainable conservation requires the engagement of all interested parties and the integration of their needs into resource management. The British NGO ReefDoctor has adopted this approach in establishing the first community-protected site in the Bay of Ranobe, the Massif des Roses. This is a large coral patch with a high percentage of live coral cover (38%) and important fish diversity compared to other sites surveyed in the lagoon. Since 25 May 2007 it has been legally recognised as a community managed marine reserve under temporary protection where fishing is banned. Tourists must now pay an entry fee to visit the site, with the proceeds contributing to the funding of community projects. In conjunction with the protection of this site, ReefDoctor has worked with local people, regional and local government, tour operators and hotels, and conservation organisations to set up ‘FIMIHARA’, an association representative of local people responsible for the management of this site and the development of sustainable conservation initiatives in the Bay of Ranobe. This paper explains the approach taken by ReefDoctor, by setting up and working with FIMIHARA, to protect the Massif des Roses site and develop other conservation initiatives and community projects in the Bay of Ranobe. RÉSUMÉ La baie de Ranobe, au sud-ouest de Madagascar, autrefois remarquable pour sa biodiversité et l’abondance de la pêche, est de plus en plus menacée par la surpêche, la sédimentation, la pollution et le tourisme. Le déclin de l’état de santé du récif corallien se reflète dans la diminution de la productivité des pêcheries et dans les suivis de la biodiversité marine. La situation est à présent critique car les ressources marines associées au récif assurent la subsistance des populations côtières vivant le long de la baie. Nous considérons ici qu’une protection pérenne nécessite un engagement concret de toutes les parties prenantes - en particulier des communautés locales - et que leurs besoins soient intégrés dans la gestion des ressources. L’ONG ReefDoctor a mis en oeuvre cette approche lors de la création de la première réserve marine dans la baie de Ranobe gérée par la communauté locale, le Massif des Roses. Cette réserve est constituée d’un grand massif de corail largement couvert de coraux et abritant une importante diversité de poissons par rapport au reste du lagon. Depuis le 25 mai 2007, ce site est légalement reconnu comme réserve marine communautaire avec un statut de protection temporaire ; la pêche et les pratiques destructrices associées au tourisme y sont interdites. De plus, les touristes doivent désormais payer un droit d’entrée pour visiter le site, qui contribue au financement de projets communautaires. En parallèle avec la protection du site, ReefDoctor a travaillé avec les communautés locales, les responsables nationaux et régionaux du gouvernement, les opérateurs touristiques et diverses organisations de protection de la nature pour créer l’association FIMIHARA, représentative de la population locale. Cette association, qui a un statut légal depuis le 11 avril 2007, a pour but d’améliorer la qualité de vie de ceux qui vivent le long de la baie de Ranobe et de mettre en oeuvre des projets de conservation des ressources marines et terrestres dans la région de la baie de Ranobe. La création de la réserve marine communautaire du Massif des Roses a rapidement connu le succès qui s’est traduit par la vente de plus d’un millier de tickets, mais l’association FIMIHARA doit encore faire face à de nombreux défis. L’objectif principal de l’association à long terme est de développer son indépendance par rapport à l’ONG ReefDoctor et sa capacité à gérer indépendamment les ressources marines de la baie de Ranobe dont les communautés locales dépendent pour leur survie

    Repurposing Anti-Inflammasome NRTIs for Improving Insulin Sensitivity and Reducing Type 2 Diabetes Development

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    Innate immune signaling through the NLRP3 inflammasome is activated by multiple diabetes-related stressors, but whether targeting the inflammasome is beneficial for diabetes is still unclear. Nucleoside reverse-transcriptase inhibitors (NRTI), drugs approved to treat HIV-1 and hepatitis B infections, also block inflammasome activation. Here, we show, by analyzing five health insurance databases, that the adjusted risk of incident diabetes is 33% lower in patients with NRTI exposure among 128,861 patients with HIV-1 or hepatitis B (adjusted hazard ratio for NRTI exposure, 0.673; 95% confidence interval, 0.638 to 0.710; P \u3c 0.0001; 95% prediction interval, 0.618 to 0.734). Meanwhile, an NRTI, lamivudine, improves insulin sensitivity and reduces inflammasome activation in diabetic and insulin resistance-induced human cells, as well as in mice fed with high-fat chow; mechanistically, inflammasome-activating short interspersed nuclear element (SINE) transcripts are elevated, whereas SINE-catabolizing DICER1 is reduced, in diabetic cells and mice. These data suggest the possibility of repurposing an approved class of drugs for prevention of diabetes

    Differential limit on the extremely-high-energy cosmic neutrino flux in the presence of astrophysical background from nine years of IceCube data

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    We report a quasi-differential upper limit on the extremely-high-energy (EHE) neutrino flux above 5×1065\times 10^{6} GeV based on an analysis of nine years of IceCube data. The astrophysical neutrino flux measured by IceCube extends to PeV energies, and it is a background flux when searching for an independent signal flux at higher energies, such as the cosmogenic neutrino signal. We have developed a new method to place robust limits on the EHE neutrino flux in the presence of an astrophysical background, whose spectrum has yet to be understood with high precision at PeV energies. A distinct event with a deposited energy above 10610^{6} GeV was found in the new two-year sample, in addition to the one event previously found in the seven-year EHE neutrino search. These two events represent a neutrino flux that is incompatible with predictions for a cosmogenic neutrino flux and are considered to be an astrophysical background in the current study. The obtained limit is the most stringent to date in the energy range between 5×1065 \times 10^{6} and 5×10105 \times 10^{10} GeV. This result constrains neutrino models predicting a three-flavor neutrino flux of $E_\nu^2\phi_{\nu_e+\nu_\mu+\nu_\tau}\simeq2\times 10^{-8}\ {\rm GeV}/{\rm cm}^2\ \sec\ {\rm sr}at at 10^9\ {\rm GeV}$. A significant part of the parameter-space for EHE neutrino production scenarios assuming a proton-dominated composition of ultra-high-energy cosmic rays is excluded.Comment: The version accepted for publication in Physical Review

    Measurements of branching fraction ratios and CP-asymmetries in suppressed B^- -> D(-> K^+ pi^-)K^- and B^- -> D(-> K^+ pi^-)pi^- decays

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    We report the first reconstruction in hadron collisions of the suppressed decays B^- -> D(-> K^+ pi^-)K^- and B^- -> D(-> K^+ pi^-)pi^-, sensitive to the CKM phase gamma, using data from 7 fb^-1 of integrated luminosity collected by the CDF II detector at the Tevatron collider. We reconstruct a signal for the B^- -> D(-> K^+ pi^-)K^- suppressed mode with a significance of 3.2 standard deviations, and measure the ratios of the suppressed to favored branching fractions R(K) = [22.0 \pm 8.6(stat)\pm 2.6(syst)]\times 10^-3, R^+(K) = [42.6\pm 13.7(stat)\pm 2.8(syst)]\times 10^-3, R^-(K)= [3.8\pm 10.3(stat)\pm 2.7(syst]\times 10^-3, as well as the direct CP-violating asymmetry A(K) = -0.82\pm 0.44(stat)\pm 0.09(syst) of this mode. Corresponding quantities for B^- -> D(-> K^+ pi^-)pi^- decay are also reported.Comment: 8 pages, 1 figure, accepted by Phys.Rev.D Rapid Communications for Publicatio
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