1,058 research outputs found

    Elastic Tensor of Sr2_2RuO4_4

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    The six independent elastic constants of Sr2_2RuO4_4 were determined using resonant ultrasound spectroscopy on a high-quality single-crystal specimen. The constants are in excellent agreement with those obtained from pulse-echo experiments performed on a sample cut from the same ingot. A calculation of the Debye temperature using the measured constants agrees well with values obtained from both specific heat and M\"{o}ssbauer measurements.Comment: 4 pages, 2 figures, 2 tables, submitted to PR

    Open and reproducible science practices in psychoneuroendocrinology: Opportunities to foster scientific progress

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    This perspective article was written by invitation of the editors in chief as a summary and extension of the symposium entitled Psychoneuroendocrine Research in the Era of the Replication Crisis which was held at the virtual meeting of the International Society of Psychoneuroendocrinology 2021. It highlights the opportunities presented by the application of open and reproducible scientific practices in psychoneuroendocrinology (PNE), an interdisciplinary field at the intersection of psychology, endocrinology, immunology, neurology, and psychiatry. It conveys an introduction to the topics preregistration, registered reports, quantifying the impact of equally-well justifiable analysis decisions, and open data and scripts, while emphasizing ‘selfish’ reasons to adopt such practices as individual researcher. Complementary to the call for adoption of open science practices, we highlight the need for methodological best practice guidelines in the field of PNE, which could further contribute to enhancing replicability of results. We propose concrete steps for future actions and provide links to additional resources for those interested in adopting open and reproducible science practices in future studies

    Shape-based peak identification for ChIP-Seq

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    We present a new algorithm for the identification of bound regions from ChIP-seq experiments. Our method for identifying statistically significant peaks from read coverage is inspired by the notion of persistence in topological data analysis and provides a non-parametric approach that is robust to noise in experiments. Specifically, our method reduces the peak calling problem to the study of tree-based statistics derived from the data. We demonstrate the accuracy of our method on existing datasets, and we show that it can discover previously missed regions and can more clearly discriminate between multiple binding events. The software T-PIC (Tree shape Peak Identification for ChIP-Seq) is available at http://math.berkeley.edu/~vhower/tpic.htmlComment: 12 pages, 6 figure

    Ultrasonic attenuation in magnetic fields for superconducting states with line nodes in Sr2RuO4

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    We calculate the ultrasonic attenuation in magnetic fields for superconducting states with line nodes vertical or horizontal relative to the RuO_2 planes. This theory, which is valid for fields near Hc2 and not too low temperatures, takes into account the effects of supercurrent flow and Andreev scattering by the Abrikosov vortex lattice. For rotating in-plane field H(theta) the attenuation alpha(theta)exhibits variations of fourfold symmetry in the rotation angle theta. In the case of vertical nodes, the transverse T100 sound mode yields the weakest(linear)H and T dependence of alpha, while the longitudinal L100 mode yields a stronger (quadratic) H and T dependence. This is in strong contrast to the case of horizontal line nodes where alpha is the same for the T100 and L100 modes (apart from a shift of pi/4 in field direction) and is roughly a quadratic function of H and T. Thus we conclude that measurements of alpha in in-plane magnetic fields for different in-plane sound modes may be an important tool for probing the nodal structure of the gap in Sr_2RuO_4.Comment: 5 pages, 6 figures, replaced in non-preprint form, to appear in Phys. Rev.

    More on FOX News: FOXA1 on the horizon of estrogen receptor function and endocrine response

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    Estrogen receptor α (ER) is a major driver of breast cancer and the target of endocrine therapy. Full disclosure of the cofactors regulating ER interactions with chromatin and its transcriptional regulatory activity is still elusive. Novel genome-wide profiling tools have mapped ER binding events in breast cancer cells and delineated cofactors important in ER activity. Among these, the Forkhead protein FOXA1 is emerging as a key factor dictating global chromatin structure and the transcriptional function of ER in breast and non-breast cancer cells. The significance of FOXA1 in the chromatin interactions and transcriptional regulation of both estrogen- and tamoxifen-bound ER, and in supporting tamoxifen-resistant cell growth, may impact current endocrine therapies

    Assessment of the cortisol awakening response: expert consensus guidelines

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    The cortisol awakening response (CAR), the marked increase in cortisol secretion over the first 30–45 min after morning awakening, has been related to a wide range of psychosocial, physical and mental health parameters, making it a key variable for psychoneuroendocrinological research. The CAR is typically assessed from self-collection of saliva samples within the domestic setting. While this confers ecological validity, it lacks direct researcher oversight which can be problematic as the validity of CAR measurement critically relies on participants closely following a timed sampling schedule, beginning with the moment of awakening. Researchers assessing the CAR thus need to take important steps to maximize and monitor saliva sampling accuracy as well as consider a range of other relevant methodological factors. To promote best practice of future research in this field, the International Society of Psychoneuroendocrinology initiated an expert panel charged with (i) summarizing relevant evidence and collective experience on methodological factors affecting CAR assessment and (ii) formulating clear consensus guidelines for future research. The present report summarizes the results of this undertaking. Consensus guidelines are presented on central aspects of CAR assessment, including objective control of sampling accuracy/adherence, participant instructions, covariate accounting, sampling protocols, quantification strategies as well as reporting and interpreting of CAR data. Meeting these methodological standards in future research will create more powerful research designs, thus yielding more reliable and reproducible results and helping to further advance understanding in this evolving field of research

    Review on the cost optimization of microgrids via particle swarm optimization

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    Economic analysis is an important tool in evaluating the performances of microgrid (MG) operations and sizing. Optimization techniques are required for operating and sizing an MG as economically as possible. Various optimization approaches are applied to MGs, which include classic and artificial intelligence techniques. Particle swarm optimization (PSO) is one of the most frequently used methods for cost optimization due to its high performance and flexibility. PSO has various versions and can be combined with other intelligent methods to realize improved performance optimization. This paper reviews the cost minimization performances of various economic models that are based on PSO with regard to MG operations and sizing. First, PSO is described, and its performance is analyzed. Second, various objective functions, constraints and cost functions that are used in MG optimizations are presented. Then, various applications of PSO for MG sizing and operations are reviewed. Additionally, optimal operation costs that are related to the energy management strategy, unit commitment, economic dispatch and optimal power flow are investigated. © 2019, The Author(s)

    Interlayer pair tunneling and gap anisotropy in YBa2_2Cu3_3O7−δ_{7-\delta}

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    Recent ARPES measurement observed a large abab-axis gap anisotropy, Δ(0,π)/Δ(π,0)=1.5\Delta(0,\pi)/\Delta(\pi,0)=1.5, in clean YBa2_2Cu3_3O7−δ_{7-\delta}. This indicates that some sub-dominant component may exist in the dx2−y2d_{x^2-y^2}-wave dominant gap. We propose that the interlayer pairing tunneling contribution can be determined through the investigation of the order parameter anisotropy. Their potentially observable features in transport and spin dynamics are also studied.Comment: 4 pages, 3 figure

    Transport and the Order Parameter of Superconducting Sr2_2RuO4_4

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    Recent experiments make it appear more likely that the order parameter of the unconventional superconductor Sr2_2RuO4_4 has a spin-triplet ff-wave symmetry. We study ultrasonic absorption and thermal conductivity of superconducting Sr2_2RuO4_4 and fit to the recent data for various ff-wave candidates. It is shown that only fx2−y2f_{x^2-y^2}-wave symmetry can account qualitatively for the transport data.Comment: 4 pages, 2 figures, references added and update

    An Intrinsic Bond-Centered Electronic Glass with Unidirectional Domains in Underdoped Cuprates

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    Removing electrons from the CuO2 plane of cuprates alters the electronic correlations sufficiently to produce high-temperature superconductivity. Associated with these changes are spectral weight transfers from the high energy states of the insulator to low energies. In theory, these should be detectable as an imbalance between the tunneling rate for electron injection and extraction - a tunneling asymmetry. We introduce atomic-resolution tunneling-asymmetry imaging, finding virtually identical phenomena in two lightly hole-doped cuprates: Ca1.88Na0.12CuO2Cl2 and Bi2Sr2Dy0.2Ca0.8Cu2O8+d. Intense spatial variations in tunneling asymmetry occur primarily at the planar oxygen sites; their spatial arrangement forms a Cu-O-Cu bond centered electronic pattern without long range order but with 4a0-wide unidirectional electronic domains dispersed throughout (a0: the Cu-O-Cu distance). The emerging picture is then of a partial hole-localization within an intrinsic electronic glass evolving, at higher hole-densities, into complete delocalization and highest temperature superconductivity.Comment: 28 pages, 9 figures, published version is available at http://people.ccmr.cornell.edu/~jcdavis/mK_stm/publications/domains/index.ht
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