Intrinsic and extrinsic geometries of a tidally deformed black hole

A description of the event horizon of a perturbed Schwarzschild black hole is provided in terms of the intrinsic and extrinsic geometries of the null hypersurface. This description relies on a Gauss-Codazzi theory of null hypersurfaces embedded in spacetime, which extends the standard theory of spacelike and timelike hypersurfaces involving the first and second fundamental forms. We show that the intrinsic geometry of the event horizon is invariant under a reparameterization of the null generators, and that the extrinsic geometry depends on the parameterization. Stated differently, we show that while the extrinsic geometry depends on the choice of gauge, the intrinsic geometry is gauge invariant. We apply the formalism to solutions to the vacuum field equations that describe a tidally deformed black hole. In a first instance we consider a slowly-varying, quadrupolar tidal field imposed on the black hole, and in a second instance we examine the tide raised during a close parabolic encounter between the black hole and a small orbiting body.Comment: 27 pages, 4 figure

Strings in Homogeneous Background Spacetimes

The string equations of motion for some homogeneous (Kantowski-Sachs, Bianchi I and Bianchi IX) background spacetimes are given, and solved explicitly in some simple cases. This is motivated by the recent developments in string cosmology, where it has been shown that, under certain circumstances, such spacetimes appear as string-vacua. Both tensile and null strings are considered. Generally, it is much simpler to solve for the null strings since then we deal with the null geodesic equations of General Relativity plus some additional constraints. We consider in detail an ansatz corresponding to circular strings, and we discuss the possibility of using an elliptic-shape string ansatz in the case of homogeneous (but anisotropic) backgrounds.Comment: 25 pages, REVTE

Coral-associated bacteria demonstrate phylosymbiosis and cophylogeny

Scleractinian corals' microbial symbionts influence host health, yet how coral microbiomes assembled over evolution is not well understood. We survey bacterial and archaeal communities in phylogenetically diverse Australian corals representing more than 425 million years of diversification. We show that coral microbiomes are anatomically compartmentalized in both modern microbial ecology and evolutionary assembly. Coral mucus, tissue, and skeleton microbiomes differ in microbial community composition, richness, and response to host vs. environmental drivers. We also find evidence of coral-microbe phylosymbiosis, in which coral microbiome composition and richness reflect coral phylogeny. Surprisingly, the coral skeleton represents the most biodiverse coral microbiome, and also shows the strongest evidence of phylosymbiosis. Interactions between bacterial and coral phylogeny significantly influence the abundance of four groups of bacteria-including Endozoicomonas-like bacteria, which divide into host-generalist and host-specific subclades. Together these results trace microbial symbiosis across anatomy during the evolution of a basal animal lineage

Vibrational dynamics of a two-dimensional microgranular crystal

We study the dynamics of an ordered hexagonal monolayer of polystyrene microspheres adhered to a glass substrate coated with a thin aluminum layer. A laser-induced transient grating technique is employed to generate and detect three types of acoustic modes across the entire Brillouin zone in the Γ−K direction: low-frequency contact-based modes of the granular monolayer, high-frequency modes originating from spheroidal vibrations of the microspheres, and surface Rayleigh waves. The dispersion relation of contact-based and spheroidal modes indicates that they are collective modes of the microgranular crystal controlled by particle-particle contacts. We observe a spheroidal resonance splitting caused by the symmetry breaking due to the substrate, as well as an avoided crossing between the Rayleigh and spheroidal modes. The measurements are found to be in agreement with our analytical model.United States. Department of Energy (Grant DE-FG02-00ER15087)National Science Foundation (U.S.) (Grant CHE-1111557

Practical steps to improve chronic hepatitis C treatment in people with opioid use disorder

People with a history of injecting drugs have high prevalence of hepatitis C virus (HCV) infection, and many have opioid use disorder (OUD). Modern HCV therapies with improved efficacy and tolerability are available, but access is often limited for this group, who may be underserved for health care and face social inequity. This work develops practical steps to improve HCV care in this population. Practical steps to improve HCV care in OUD populations were developed based on clinical experience from Spain, structured assessment of published evidence. Options for improving care at engagement/screening stages include patient education programs, strong provider-patient relationship, peer support, and adoption of rapid effective screening tools. To facilitate work up/treatment, start options include simplified work up process, integration of HCV and OUD care, and continuous psychosocial support prior, during, and after HCV treatment. It is important to plan on local basis to set up a joint integrated approach between specific drug treatment services and local points of HCV care. The elements for a specific integrated program should be chosen from options identified, including education services, peer input, organization to make HCV screening and treatment easier by co-location of services, and wider access to prescribing direct-acting antiviral (DAA) therapy

Carbon Capture by Metal Oxides : Unleashing the Potential of the (111) Facet

This work was supported by the Engineering and Physical Sciences Research Council (EPSRC) via a Doctoral Training Grant for G.A.M. (EP/K0502960/1) and a Doctoral Prize Fellowship (EP/M50791X/1). Dedicated to the memory of Kenneth J. Klabunde. Supporting Information. Synthesis procedure, experimental methods, computational methods, transmission microscopy images, N2 adsorption-desorption isotherms and pore size distributions, additional CO2 adsorption isotherms and density functional theory model surfaces. This material is available free of charge via the Internet at http://pubs.acs.org.Peer reviewedPostprin

Developing a bioinformatics pipeline for Urochloa spp. mapping population: from RAD sequencing data to identification of QTL for spittlebug resistance

The development of molecular technologies for breeding tetraploid brachiaria interspecific hybrids (Urochloa spp.) was limited by its ploidy, the lack of a tetraploid Urochloa reference genome and the consequent drawback of using only simplex markers to construct linkage maps. However, the current increasing availability of open-source tools for genomic data in polyploid species has broadened the genetic resources that are available for the breeding of these forages. Using RAD sequencing data from a multiparenting mapping population, a new fully resolved genome of U. decumbens and phenotypical scoring for tolerance and antibiosis to Aeneolamia varia, we designed a bioinformatics pipeline to construct genetic maps that allow us to identify QTL associated with resistance to this spittlebug species. The next steps are to test different software and techniques for each phase in the pipeline, control the quality of the outputs and deliver accurate results from the phenotypic and genotypic data association

When the sad past is left: the mental metaphors between time, valence, and space

The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fpsyg. 2018.01019/full#supplementary-materialA mental metaphor is a strategy that consists of completing the representation of a concept with structural components of a correlating concept. Three issues were addressed here to deepen our understanding of this mechanism: the use of mental metaphors between abstract concepts, the simultaneous activation of multiple mental metaphors and the importance of the focus of attention on the relevant dimensions of a mental metaphor. In two experiments, participants made temporal or valence judgments (with their left or right hand) on verbs with a negative or positive meaning and conjugated in the past or future form, allowing for the simultaneous activation of the “time is space”, “valence is space,” and “time is valence” mental metaphors. Left-past/right-future and left-negative/right-positive congruency effects were found, and these effects were greater in the temporal and valence judgment tasks, respectively, demonstrating the importance of attentional cuing. Simultaneously, a congruency effect between the abstract concepts of time and valence (past-negative/future-positive) was observed, revealing that a mental metaphor can occur between abstract concepts and that multiple metaphors can be processed simultaneously. These results are discussed in terms of different theories within the field of mental metaphors.MO was supported by a Juan de la Cierva fellowship (JCI-2012-13046) from the Spanish Ministry of Education and Science. Research was funded by research projects PSI2012-32464 (Spanish Ministry of Economy and Competitiveness) and PSI2015-67531-P (Spanish Ministry of Economy and Competitiveness) to JS