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The orbital motion of electrons in a three-dimensional solid can generate a pseudoscalar magnetoelectric coupling $θ$, a fact we derive for the single-particle case using a recent theory of polarization in weakly inhomogeneous materials. This polarizability $θ$ is the same parameter that appears in the "axion electrodynamics" Lagrangian $Δ{\cal L}_{EM} = (θe^2 / 2 πh) {\bf E} \cdot {\bf B}$, which is known to describe the unusual magnetoelectric properties of the three-dimensional topological insulator ($θ=π$). We compute $θ$ for a simple model that accesses the topological insulator and discuss its connection to the surface Hall conductivity. The orbital magnetoelectric polarizability can be generalized to the many-particle wavefunction and defines the 3D topological insulator, like the IQHE, in terms of a topological ground-state response function.
Simplified models provide a useful way to study the impacts of a small number of new particles on experimental observables and the interplay of those observables, without the need to construct an underlying theory. In this study, we perform global fits of simplified dark matter models with GAMBIT using an up-to-date set of likelihoods for indirect detection, direct detection and collider searches. We investigate models in which a scalar or fermionic dark matter candidate couples to quarks via an s-channel vector mediator. Large parts of parameter space survive for each model. In the case of Dirac or Majorana fermion dark matter, excesses in LHC monojet searches and relic density limits tend to prefer the resonance region, where the dark matter has approximately half the mass of the mediator. A combination of vector and axial-vector couplings to the Dirac candidate also leads to competing constraints from direct detection and unitarity violation.
Summary Powdery mildews and other obligate biotrophic pathogens are highly adapted to their hosts and often show limited host ranges. One facet of such host specialization is likely to be penetration of the host cell wall, a major barrier to infection. A mutation in the pmr5 gene rendered Arabidopsis resistant to the powdery mildew species Erysiphe cichoracearum and Erysiphe orontii , but not to the unrelated pathogens Pseudomonas syringae or Peronospora parasitica . PMR5 belongs to a large family of plant‐specific genes of unknown function. pmr5 ‐mediated resistance did not require signaling through either the salicylic acid or jasmonic acid/ethylene defense pathways, suggesting resistance in this mutant may be due either to the loss of a susceptibility factor or to the activation of a novel form of defense. Based on Fourier transform infrared analysis, the pmr5 cell walls were enriched in pectin and exhibited a reduced degree of pectin modification relative to wild‐type cell walls. In addition, the mutant had smaller cells, suggesting a defect in cell expansion. A double mutant with pmr6 (defective in a glycosylphosphatidylinositol‐anchored pectate lyase‐like gene) exhibited a strong increase in total uronic acid content and a more severe reduction in size, relative to the single mutants, suggesting that the two genes affect pectin composition, either directly or indirectly, via different mechanisms. These two mutants highlight the importance of the host cell wall in plant–microbe interactions.
The Medicare Catastrophic Coverage Act (CHI), signed into law in 1988, represented the greatest expansion of Medicare since the program's establishment in 1965. Although the nature and extent of the political fallout from these events is yet to be fully appreciated, the short life and painful death of CHI deserves attention. The Catastrophic Coverage Act, which in part reflects changing assumptions regarding reciprocal obligations as they apply to the elderly, provides an excellent case study of a policy development better understood through a combined political and moral economy framework. The structure of CHI taxation also violated moral economy notions of fairness in asking less than 6 percent of America's population to do what was expected of no one else: to pay a special tax for benefits for their age group. A political economy framework questions the basic assumptions of pluralism and overcomes many of its limitations.
STUDY OBJECTIVES: To evaluate the prevalence of severe insomnia symptoms and the extent to which they are associated with daytime impairments in comorbid mood and anxiety disorders. DESIGN: Nationally representative cross-sectional survey. SETTING: National Comorbidity Survey-Replication (NCS-R). PARTICIPANTS: There were 5,692 NCS-R respondents with no mood or anxiety disorder (n = 3,711), mood disorders only (n = 327), anxiety disorders only (n = 1,137), and coexisting mood and anxiety disorders (n = 517). INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition disorders and severe insomnia symptoms in the past year were assessed using the World Health Organization (WHO) Composite International Diagnostic Interview. The World Health Organization Disability Assessment Schedule (WHO-DAS) indexed eight domains of daytime impairment in the past 30 days, which included self-care, mobility, cognition, social functioning, time out of role, and four components of productive role functioning. Respondents with comorbid mood and anxiety disorders had significantly higher rates of severe insomnia complaints (42.1-62.8%) relative to the three other groups. Severe insomnia complaints were also significantly more prevalent in individuals with mood (25.2-45.6%) or anxiety disorders only (24.9-45.5%) relative to those with no disorder (12.4-24.3%). Moreover, endorsing a severe insomnia complaint in the past year was associated with increased days of impairment across all past-month WHO-DAS domains for respondents with mood-anxiety comorbidity. For the remaining groups, severe insomnia complaints were related to increased days of impairment across all domains except self-care, and additionally mobility for the group with mood disorders only. CONCLUSIONS: Comorbid mood and anxiety disorders are associated with high rates of severe insomnia complaints, which were independently associated with substantial functional impairment. CITATION: Soehner AM; Harvey AG. Prevalence and functional consequences of severe insomnia symptoms in mood and anxiety disorders: results from a nationally representative sample. SLEEP 2012;35(10):1367–1375.
ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTLigand Effects in Homogeneous Au CatalysisDavid J. Gorin, Benjamin D. Sherry, and F. Dean Toste*View Author Information Department of Chemistry, University of California, Berkeley, California, 94720* Author for correspondence. Telephone: 510-642-2850. Fax: 510-643-9480. Email: [email protected].Cite this: Chem. Rev. 2008, 108, 8, 3351–3378Publication Date (Web):July 25, 2008Publication History Received13 February 2008Published online25 July 2008Published inissue 1 August 2008https://pubs.acs.org/doi/10.1021/cr068430ghttps://doi.org/10.1021/cr068430greview-articleACS PublicationsCopyright © 2008 American Chemical SocietyRequest reuse permissionsArticle Views19133Altmetric-Citations1934LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Catalysts,Cyclization,Gold,Hydrocarbons,Ligands Get e-Alerts
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
We study the real-time dynamics of spin chains driven out of thermal\nequilibrium by an initial temperature gradient T_L \\neq T_R using density\nmatrix renormalization group methods. We demonstrate that the nonequilibrium\nenergy current saturates fast to a finite value if the linear-response thermal\nconductivity is infinite, i.e. if the Drude weight D is nonzero. Our data\nsuggests that a nonintegrable dimerized chain might support such\ndissipationless transport (D>0). We show that the steady-state value J_E of the\ncurrent for arbitrary T_L \\neq T_R is of the functional form J_E=f(T_L)-f(T_R),\ni.e. it is completely determined by the linear conductance. We argue for this\nfunctional form, which is essentially a Stefan-Boltzmann law in this integrable\nmodel; for the XXX ferromagnet, f can be computed via thermodynamic Bethe\nansatz in good agreement with the numerics. Inhomogeneous systems exhibiting\ndifferent bulk parameters as well as Luttinger liquid boundary physics induced\nby single impurities are discussed briefly.\n
Abstract not Available.
Nature has developed a wide range of materials with specific properties matched to function by combining minerals and organic polymers into hierarchical structures spanning multiple length-scales. For instance, some materials, such as antler, mimic bone structure with a lower mineralization to provide toughness [1,2], whereas many fish scales have graded material properties from the hard, penetration-resistant outer layer to the adaptive lamellae in the collagen fibril subsurface [3,4]. Indeed, biological systems represent an inexhaustible source of inspiration to materials scientists by offering potential solutions for the development of new generations of structural and functional materials [5]. Nature's key role here is in the complex hierarchical assembly of the structural architectures [6]. The concept of multiscale hierarchical structures, where the microstructure at each level is tailored to local needs, allows the adaptation and optimization of the material form and structure at each level of hierarchy to meet specific functions. Indeed, the complexity and symbiosis of structural biological materials has generated enormous interest of late, primarily because these composite biological systems exhibit mechanical properties that are invariably far superior to those of their individual constituents [7].
Abstract A general substructure method for analysis of response of structures to earthquake ground motion, including the effects of structure‐soil interaction, is presented. The method is applicable to complex structures idealized as finite element systems and the soil region treated as either a continuum, for example as a viscoelastic halfspace, or idealized as a finite element system. The halfspace idealization permits reliable analysis for sites where essentially similar soils extend to large depths and there is no rigid boundary such as soil‐rock interface. For sites where layers of soft soil are underlain by rock at shallow depth, finite element idealization of the soil region is appropriate; in this case, the direct and substructure methods would lead to equivalent results but the latter provides the better alternative. Treating the free field motion directly as the earthquake input in the substructure method eliminates the deconvolution calculations and the related assumption—regarding type and direction of earthquake waves—required in the direct method. Spatial variations in the input motion along the structure‐soil interface of embedded structures or along the base of long surface supported structures are included in the formulation. The substructure method is computationally efficient because the two substructures—the structure and the soil region—are analysed separately; and, more important, it permits taking advantage of the important feature that response to earthquake ground motion is essentially contained in the lower few natural modes of vibration of the structure on fixed base.
