1,643 research outputs found

    NMR relaxation time around a vortex in stripe superconductors

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    Site-dependent NMR relaxation time T1(r)T_1({\bf r}) is calculated in the vortex state using the Bogoliubov-de Gennes theory, taking account of possible "field-induced stripe'' states in which the magnetism arises locally around a vortex core in d-wave superconductivity. The recently observed huge enhancement T1−1(r)T_1^{-1}({\bf r}) below TcT_c at a core site in Tl2_2Ba2_2CuO6_6 is explained. The field-induced stripe picture explains consistently other relevant STM and neutron experiments.Comment: 4 pages, 4 figure

    Finding feasible action towards urban transformations

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    While innovative approaches to urban transformations are increasingly proposed, scholars often overlook challenges faced by endogenous actors (e.g. urban planners) tasked with taking action within non-ideal, real-world settings. Here we argue that an ‘inside’ view of transformations (focused on judgment in practice) is needed to complement existing ‘outside’ views (focused on assessment), where the feasibility of action becomes a central concern. This recasts urban transformations in a discretised perspective. It suggests a view of transformation pathways as both directed and stochastic, and emergent from an unfolding series of ‘fuzzy action moments’. Principles for bridging urban science and planning are derived.Peer reviewe

    GINZBURG-LANDAU THEORY OF VORTICES IN dd-WAVE SUPERCONDUCTORS

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    Ginzburg-Landau theory is used to study the properties of single vortices and of the Abrikosov vortex lattice in a dx2−y2d_{x^2-y^2} superconductor. For a single vortex, the ss-wave order parameter has the expected four-lobe structure in a ring around the core and falls off like 1/r21/r^2 at large distances. The topological structure of the ss-wave order parameter consists of one counter-rotating unit vortex, centered at the core, surrounded by four symmetrically placed positive unit vortices. The Abrikosov lattice is shown to have a triangular structure close to TcT_c and an oblique structure at lower temperatures. Comparison is made to recent neutron scattering data.Comment: 4 pages, REVTeX, 3 figures available upon reques

    Suomen maataloushistorian pÀÀlinjat

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    Suomen maatalouden historia on ollut viljelijÀn kamppailua toimeentulonsa puolesta vaihtelevissa olosuhteissa. Maatilatalouden rakennemuutokset ja viljelymenetelmien vaihtaminen ovat olleet tÀrkeitÀ keinoja maanviljelijÀn koettaessa mukautua alati liikkeellÀ olevaan taloudelliseen kehitykseen. PerinnÀisen maatalouden kaudella esihistoriallisen ajan lopulta 1800-luvulle tekninen kehitys oli varsin hidasta, mutta nopeampaa kehitystÀ tapahtui taloudellisen toiminnan alalla maatilatalouden painopisteen siirtyessÀ jatkuvasti sektorilta toiselle tai rinnakkaisesta viljelymenetelmÀstÀ toiseen. KÀsitys maatalouskehityksemme staattisesta luonteesta perinnÀisen maatalouden kaudella, joka perustuu yksipuolisesti teknisen kehityksen hitauteen, osoittautuu nÀin ollen harhakuvaksi. Viimeisen sadan vuoden aikana maatalouskehityksen luonne on suuresti muuttunut. Kehitykselle on ollut luonteenomaista nopeasti edistyvÀ maataloustekniikka ja siirtyminen omavaraistaloudesta vaihdantatalouteen. Seurauksena on ollut sopeutumisvaikeuksia sekÀ maatalouden tuotantoyksiköille, maatiloille, ettÀ maatalousvÀestölle. Huomattavalta osalta nÀistÀ sopeutumisvaikeuksista johtuu, ettÀ maatalouden taloudellisen ja sosiaalisen kehityksen vÀlillÀ on ollut kitkaa ja maatalouden tuottavuuden kasvu on jÀÀnyt jÀlkeen yleisestÀ taloudellisesta kasvusta

    ss- and dxyd_{xy}-wave components induced around a vortex in dx2−y2d_{x^2-y^2}-wave superconductors

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    Vortex structure of dx2−y2d_{x^2-y^2}-wave superconductors is microscopically analyzed in the framework of the quasi-classical Eilenberger equations. If the pairing interaction contains an ss-wave (dxyd_{xy}-wave) component in addition to a dx2−y2d_{x^2-y^2}-wave component, the ss-wave (dxyd_{xy}-wave) component of the order parameter is necessarily induced around a vortex in dx2−y2d_{x^2-y^2}-wave superconductors. The spatial distribution of the induced ss-wave and dxyd_{xy}-wave components is calculated. The ss-wave component has opposite winding number around vortex near the dx2−y2d_{x^2-y^2}-vortex core and its amplitude has the shape of a four-lobe clover. The amplitude of dxyd_{xy}-component has the shape of an octofoil. These are consistent with results based on the GL theory.Comment: RevTex,9 pages, 6 figures in a uuencoded fil

    Field induced dx2−y2+idxyd_{x^2-y^2}+id_{xy} state and marginal stability of high-Tc superconductors

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    It is shown that the {\em complex} dxyd_{xy} component is generated in d-wave superconductor in the magnetic field. As one enters superconducting state at finite field the normal to superconducting transition occurs into bulk dx2−y2+idxyd_{x^2-y^2}+i d_{xy} state . The driving force for the transition is the linear coupling between magnetic field and non zero magnetization of the dx2−y2+idxyd_{x^2-y^2}+i d_{xy} condensate. The external magnetic field violates parity and time reversal symmetries and the nodal quasiparticle states respond by generating the idxyid_{xy} component of the order parameter, with the magnitude estimated to be on the order of few Kelvin. Parity (P) and time reversal (T) symmetries are violated in this state.Comment: 4 pages, latex file with two eps figure file

    Antibody responses to nasopharyngeal carriage of Streptococcus pneumoniae in adults: A longitudinal household study

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    Background. Natural immunity to Streptococcus pneumoniae is thought to be induced by exposure to S. pneumoniae or cross-reactive antigens. No longitudinal studies of carriage of and immune responses to S. pneumoniae have been conducted using sophisticated immunological laboratory techniques.Methods. We enrolled 121 families with young children into this study. Nasopharyngeal (NP) swabs were collected monthly for 10 months from all family members and were cultured in a standard fashion. Cultured S. pneumoniae isolates were serotyped. At the beginning (month 0) and end (month 10) of the study, venous blood was collected from family members 118 years old. Serotype-specific antipolysaccharide immunoglobulin G (IgG) and functional antibody and antibodies to pneumolysin, pneumococcal surface protein A (PspA), and pneumococcal surface antigen A (PsaA) were measured in paired serum samples.Results. Levels of anticapsular IgG increased significantly after carriage of serotypes 9V, 14, 18C, 19F, and 23F by an individual or family member. For serotype 14, a higher level of anticapsular IgG at the beginning of the study was associated with reduced odds of carriage (P = .0006). There was a small (similar to 20%) but significant increase in titers of antibodies to PsaA and pneumolysin but no change in titers of antibody to PspA.Conclusions. Adults respond to NP carriage by mounting anticapsular and weak antiprotein antibody responses, and naturally induced anticapsular IgG can prevent carriage

    A semi-automatic workflow to process images from small mammal camera traps

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    Camera traps have become popular for monitoring biodiversity, but the huge amounts of image data that arise from camera trap monitoring represent a challenge and artificial intelligence is increasingly used to automatically classify large image data sets. However, it is still challenging to combine automatic classification with other steps and tools needed for efficient, quality-assured and adaptive processing of camera trap images in long-term monitoring programs. Here we propose a semi-automatic workflow to process images from small mammal cameras that combines all necessary steps from downloading camera trap images in the field to a quality checked data set ready to be used in ecological analyses. The workflow is implemented in R and includes (1) managing raw images, (2) automatic image classification, (3) quality check of automatic image labels, as well as the possibilities to (4) retrain the model with new images and to (5) manually review subsets of images to correct image labels. We illustrate the application of this workflow for the development of a new monitoring program of an Arctic small mammal community. We first trained a classification model for the specific small mammal community based on images from an initial set of camera traps. As the monitoring program evolved, the classification model was retrained with a small subset of images from new camera traps. This case study highlights the importance of model retraining in adaptive monitoring programs based on camera traps as this step in the workflow increases model performance and substantially decreases the total time needed for manually reviewing images and correcting image labels. We provide all R scripts to make the workflow accessible to other ecologists
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