11,342 research outputs found

    Suppression of cell-spreading and phagocytic activity on nano-pillared surface: in vitro experiment using hemocytes of the colonial ascidian Botryllus schlosseri.

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    Nano-scale nipple array on the body surface has been described from various invertebrates including endoparasitic and mesoparasitic copepods, but the functions of the nipple array is not well understood. Using the hydrophilized nanopillar sheets made of polystyrene as a mimetic material of the nipple arrays on the parasites\u2019 body surface, we assayed the cell spreading and phagocytosis of the hemocytes of the colonial ascidian Botryllus schlosseri. On the pillared surface, the number of spreading amebocytes and the number of phagocytizing hemocytes per unit area were always smaller than those on the flat surface (Mann-Whitney test, p < 0.05 - 0.001), probably because the effective area for the cell attachment on the pillared surface is much smaller than the area on the flat sheet. The present results supports the idea that the nipple array on the parasites' body surface reduces the innate immune reaction from the host hemocytes

    Enhancement of superconductivity near the ferromagnetic quantum critical point in UCoGe

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    We report a high-pressure single crystal study of the superconducting ferromagnet UCoGe. Ac-susceptibility and resistivity measurements under pressures up to 2.2 GPa show ferromagnetism is smoothly depressed and vanishes at a critical pressure pc=1.4p_c = 1.4 GPa. Near the ferromagnetic critical point superconductivity is enhanced. Upper-critical field measurements under pressure show Bc2(0)B_{c2}(0) attains remarkably large values, which provides solid evidence for spin-triplet superconductivity over the whole pressure range. The obtained p−Tp-T phase diagram reveals superconductivity is closely connected to a ferromagnetic quantum critical point hidden under the superconducting `dome'.Comment: 4 pages, 3 figures; accepted for publication in PR

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    Muon spin rotation and relaxation in the superconducting ferromagnet UCoGe

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    We report zero-field muon spin rotation and relaxation measurements on the superconducting ferromagnet UCoGe. Weak itinerant ferromagnetic order is detected by a spontaneous muon spin precession frequency below the Curie temperature TC=3T_C = 3 K. The μ+\mu^+ precession frequency persists below the bulk superconducting transition temperature Tsc=0.5T_{sc} = 0.5 K, where it measures a local magnetic field Bloc=0.015B_{loc} = 0.015 T. The amplitude of the μ\muSR signal provides unambiguous proof for ferromagnetism present in the whole sample volume. We conclude ferromagnetism coexists with superconductivity on the microscopic scale.Comment: 4 pages, 3 figures, accepted for publication in PR

    Introducing passive matched field acoustic tomography

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    In acoustic tomography sea-basin environmental parameters such as temperature profiles and current-velocities are derived, when ray propagation models are adopted, by the travel time estimates relative to the identifiable ray paths. The transmitted signals are either single frequency, or impulsive, or intermittent and deterministic. When the wavelength is comparable with the scale lengths present in the propagation scenario, Matched Field Tomography (MFT) is used, entailing the consideration of waveguide modes instead of rays. A new concept in tomography is introduced in the paper, that employs passively the noise emitted by ships of opportunity (cargoes, ferries) as source signals. The passive technique is acoustic-pollution-free, and if a basin is selected in which a regular ship traffic occurs data can be received on a regular schedule, with no transmission cost. A novel array pre-processor for passive tomography is introduced, such that the signal structure at the pre-processor output is nearly the same as that obtainable in the case of single-frequency source signals. Hence, at the pre-processor output all the tomographic inversion methods valid for active tomography employing single-frequency sources can be applied. The differences between active and passive tomography are pointed out and the potential of passive techniques is illustrated by simple propagation scenarios adopting either rays or waveguide modes

    Mechanical Systems: Symmetry and Reduction

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    Reduction theory is concerned with mechanical systems with symmetries. It constructs a lower dimensional reduced space in which associated conservation laws are taken out and symmetries are \factored out" and studies the relation between the dynamics of the given system with the dynamics on the reduced space. This subject is important in many areas, such as stability of relative equilibria, geometric phases and integrable systems

    INTEREST: INteractive Tool for Exploring REsults from Simulation sTudies

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    Simulation studies allow us to explore the properties of statistical methods. They provide a powerful tool with a multiplicity of aims; among others: evaluating and comparing new or existing statistical methods, assessing violations of modelling assumptions, helping with the understanding of statistical concepts, and supporting the design of clinical trials. The increased availability of powerful computational tools and usable software has contributed to the rise of simulation studies in the current literature. However, simulation studies involve increasingly complex designs, making it difficult to provide all relevant results clearly. Dissemination of results plays a focal role in simulation studies: it can drive applied analysts to use methods that have been shown to perform well in their settings, guide researchers to develop new methods in a promising direction, and provide insights into less established methods. It is crucial that we can digest relevant results of simulation studies. Therefore, we developed INTEREST: an INteractive Tool for Exploring REsults from Simulation sTudies. The tool has been developed using the Shiny framework in R and is available as a web app or as a standalone package. It requires uploading a tidy format dataset with the results of a simulation study in R, Stata, SAS, SPSS, or comma-separated format. A variety of performance measures are estimated automatically along with Monte Carlo standard errors; results and performance summaries are displayed both in tabular and graphical fashion, with a wide variety of available plots. Consequently, the reader can focus on simulation parameters and estimands of most interest. In conclusion, INTEREST can facilitate the investigation of results from simulation studies and supplement the reporting of results, allowing researchers to share detailed results from their simulations and readers to explore them freely

    Pitch-Luminance Crossmodal Correspondence in the Baby Chick: An Investigation on Predisposed and Learned Processes.

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    Our senses are constantly reached by a multitude of stimuli from all different sensory modalities. To create a coherent representation of the environment, we must integrate the various unimodal inputs that refer to the same object into a single multimodal representation. In some cases, however, we tend to bind certain properties of the stimuli without any apparent reason, which is a phenomenon named crossmodal correspondence. For instance, we match a spiky or a rounded shape with the sound "Kiki" or "Bouba", respectively. Similarly, we associate the left hemispace with low luminance and the right one with high luminance. Instances of crossmodal correspondences were described also in other mammals, and recently, a case of space-luminance crossmodal correspondence was reported in birds (i.e., domestic chicks). Here, we investigate the presence of pitch-luminance crossmodal correspondence in three-day-old chicks, employing experimental methods that exploit either predisposed or learned processes. While failing to report evidence for this phenomenon, we discuss the difference between statistical and structural crossmodal correspondences and the possible role of environmental factors in determining their emergence. Moreover, we discuss the importance of the different experimental methodologies to investigate distinct aspects of this perceptual phenomenon to reach a deeper understanding and unveil the role of innate vs. learned mechanisms

    Androgens and Severe Insulin Resistance States: Basic and Clinical Aspects

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    Hyperandrogenism with or without polycystic ovary syndrome can be sustained by an extreme form of insulin resistance (IR), and is thus a secondary form of hyperandrogenism, which may be due to a defect in insulin signal transduction or in the adipose tissue. Severe IR due to adipose tissue dysfunction is the most frequent form, which may be the result of a deficiency in the adipose tissue, that is, the lipodystrophies, or to the unrestrained accumulation of adipose tissue. These forms are in some cases produced by a single-gene defect. The diagnosis remains predominantly clinical by examining patients in their underwear and looking out for clinical hallmarks, supported by biochemical biomarkers. Gene screening is necessary to corroborate the diagnosis of some forms. Clinicians who deal with hyperandrogenic disorders should be alerted to the forms that are secondary to severe IR, as they are not as uncommon as often imagined and frequently respond to tailored therapies
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