311 research outputs found

    Detection of Striped Superconductors Using Magnetic Field Modulated Josephson Effect

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    In a very interesting recent Letter\cite{berg}, the authors suggested that a novel form of superconducting state is realized in La2−x_{2-x}Bax_xCuO4_4 with xx close to 1/8. This suggestion was based on experiments\cite{li} on this compound which found predominantly two-dimensional (2D) characters of the superconducting state, with extremely weak interplane coupling. Later this specific form of superconducting state was termed striped superconductors\cite{berg08}. The purpose of this note is to point out that the suggested form\cite{berg} of the superconducting order parameter can be detected directly using magnetic field modulated Josephson effect.Comment: Expanded version as appeared in prin

    An analytical model for CDMA downlink rate optimization taking into account uplink coverage restriction

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    This paper models and analyzes downlink and uplink power assignment in Code Division Multiple Access (CDMA) mobile networks. By discretizing the area into small segments, the power requirements are characterized via a matrix representation that separates user and system characteristics. We obtain a closed-form analytical expression of the so-called Perron-Frobenius eigenvalue of that matrix, which provides a quick assessment of the feasibility of the power assignment for each distribution of calls over the segments. Our results allow for a fast evaluation of outage and blocking probabilities. The result also enables a quick evaluation of feasibility that may be used for capacity allocation. Our combined downlink and uplink feasibility model is applied to determine maximal system throughput in terms of downlink rates. \u

    Spin matrix elements in 2D Ising model on the finite lattice

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    We present explicit formulas for all spin matrix elements in the 2D Ising model with the nearest neighbor interaction on the finite periodic square lattice. These expressions generalize the known results [Phys. Rev. D19, (1979), 2477--2479; hep-th/0107117; hep-th/0112167] (coincide with them in the appropriate limits) and fulfill the test of straightforward transfer matrix calculations for finite NN.Comment: old paper (2003) posted for archival purpose

    Change in incidence, characteristics and management of colorectal neuroendocrine tumours in the Netherlands in the last decade

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    Background Neuroendocrine tumours (NETs) are rare. However, a rising incidence has been reported over the past decades. For colorectal NETs, this is presumably caused by an increased awareness of colorectal diseases and colonoscopic procedures. This study aims to analyse the change in incidence of colorectal NETs, characteristics and management and evaluate the proportion of colorectal NETs detected in a national colorectal cancer (CRC) screening programme. Methods Histopathological reports on colorectal well-differentiated NETs detected between 2006 and 2016 were collected from the Dutch pathology database (PALGA) containing nationwide histo- and cytopathology reports of all pathology laboratories in the Netherlands. Results Colorectal NETs were detected in 1055 individuals. Increasing incidence rates were observed from 0.36 per 100,000 inhabitants in 2006 to 0.75 per 100,000 inhabitants in 2011 (p value < 0.001), remaining stable afterward. Most NETs were grade I (73.5%) and detected in the rectum (76.4%). The majority (88.2%) were detected by colonoscopy, and the final intervention depended significantly on primary location of the tumour; 94.6% of rectal NETs were endoscopically removed, whereas 61.0% of colonic NETs were removed by surgery. There was an increase in local excision both of rectal and colonic NETs over the years instead of radical resection. Screening for CRC started in 2014 and contributed by detecting 32% of the diagnosed colorectal NETs within the invited age group, of which 94.6% were detected at an early stage. Conclusion The incidence of reported colorectal NETs in the Netherlands doubled over the last decade. The Dutch CRC screening programme had a clear contribution to colorectal NETs incidence among its target population. A shift to more local management of detected lesions was observed over time

    The Self Model and the Conception of Biological Identity in Immunology

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    The self/non-self model, first proposed by F.M. Burnet, has dominated immunology for sixty years now. According to this model, any foreign element will trigger an immune reaction in an organism, whereas endogenous elements will not, in normal circumstances, induce an immune reaction. In this paper we show that the self/non-self model is no longer an appropriate explanation of experimental data in immunology, and that this inadequacy may be rooted in an excessively strong metaphysical conception of biological identity. We suggest that another hypothesis, one based on the notion of continuity, gives a better account of immune phenomena. Finally, we underscore the mapping between this metaphysical deflation from self to continuity in immunology and the philosophical debate between substantialism and empiricism about identity

    Real and Virtual Compton Scattering: the nucleon polarisabilities

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    We give an overview of low-energy Compton scattering (gamma^(*) p --> gamma p) with a real or virtual incoming photon. These processes allow the investigation of one of the fundamental properties of the nucleon, i.e. how its internal structure deforms under an applied static electromagnetic field. Our knowledge of nucleon polarisabilities and their generalization to non-zero four-momentum transfer will be reviewed, including the presently ongoing experiments and future perspectives.Comment: 20 pages, 12 figures. Minireview/Proceedings of "Many-Body Structure of Strongly Interacting Systems", Mainz, Germany, Feb. 23-25 2011 . V2: typos corrected. version to appear in EPJ Special Topic

    Generalized Polarizabilities of the Nucleon in Chiral Effective Theories

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    Using the techniques of chiral effective field theories we evaluate the so called generalized polarizabilities of the nucleon, which characterize the structure dependent components in virtual Compton scattering (VCS) as probed in the electron scattering reaction e N \to e' N gamma. Results are given for both spin-dependent and spin-independent structure effects to O(p^3) in SU(2) Heavy Baryon Chiral Perturbation Theory and to O(epsilon^3) in the SU(2) Small Scale Expansion. Finally we compare our calculations with results from the pioneering VCS experiment on the proton from Mainz.Comment: 39 pages, 12 figures, revte

    A combined linkage, microarray and exome analysis suggests MAP3K11 as a candidate gene for left ventricular hypertrophy

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    Background: Electrocardiographic measures of left ventricular hypertrophy (LVH) are used as predictors of cardiovascular risk. We combined linkage and association analyses to discover novel rare genetic variants involved in three such measures and two principal components derived from them. Methods: The study was conducted among participants from the Erasmus Rucphen Family Study (ERF), a Dutch family-based sample from the southwestern Netherlands. Variance components linkage analyses were performed using Merlin. Regions of interest (LOD > 1.9) were fine-mapped using microarray and exome sequence data. Results: We observed one significant LOD score for the second principal component on chromosome 15 (LOD score = 3.01) and 12 suggestive LOD scores. Several loci contained variants identified in GWAS for these traits; however, these did not explain the linkage peaks, nor did other common variants. Exome sequence data identified two associated variants after multiple testing corrections were applied. Conclusions: We did not find common SNPs explaining these linkage signals. Exome sequencing uncovered a relatively rare variant in MAPK3K11 on chromosome 11 (MAF = 0.01) that helped account for the suggestive linkage peak observed for the first principal component. Conditional analysis revealed a drop in LOD from 2.01 to 0.88 for MAP3K11, suggesting that this variant may partially explain the linkage signal at this chromosomal location. MAP3K11 is related to the JNK pathway and is a pro-apoptotic kinase that plays an important role in the induction of cardiomyocyte apoptosis in various pathologies, including LVH

    Effects of climate and atmospheric nitrogen deposition on early to mid-term stage litter decomposition across biomes

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    Litter decomposition is a key process for carbon and nutrient cycling in terrestrial ecosystems and is mainly controlled by environmental conditions, substrate quantity and quality as well as microbial community abundance and composition. In particular, the effects of climate and atmospheric nitrogen (N) deposition on litter decomposition and its temporal dynamics are of significant importance, since their effects might change over the course of the decomposition process. Within the TeaComposition initiative, we incubated Green and Rooibos teas at 524 sites across nine biomes. We assessed how macroclimate and atmospheric inorganic N deposition under current and predicted scenarios (RCP 2.6, RCP 8.5) might affect litter mass loss measured after 3 and 12 months. Our study shows that the early to mid-term mass loss at the global scale was affected predominantly by litter quality (explaining 73% and 62% of the total variance after 3 and 12 months, respectively) followed by climate and N deposition. The effects of climate were not litter-specific and became increasingly significant as decomposition progressed, with MAP explaining 2% and MAT 4% of the variation after 12 months of incubation. The effect of N deposition was litter-specific, and significant only for 12-month decomposition of Rooibos tea at the global scale. However, in the temperate biome where atmospheric N deposition rates are relatively high, the 12-month mass loss of Green and Rooibos teas decreased significantly with increasing N deposition, explaining 9.5% and 1.1% of the variance, respectively. The expected changes in macroclimate and N deposition at the global scale by the end of this century are estimated to increase the 12-month mass loss of easily decomposable litter by 1.1-3.5% and of the more stable substrates by 3.8-10.6%, relative to current mass loss. In contrast, expected changes in atmospheric N deposition will decrease the mid-term mass loss of high-quality litter by 1.4-2.2% and that of low-quality litter by 0.9-1.5% in the temperate biome. Our results suggest that projected increases in N deposition may have the capacity to dampen the climate-driven increases in litter decomposition depending on the biome and decomposition stage of substrate
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