472 research outputs found
Inflation with multiple sound speeds: A model of multiple DBI type actions and non-Gaussianities
AbstractIn this Letter we study adiabatic and isocurvature perturbations in the frame of inflation with multiple sound speeds involved. We suggest this scenario can be realized by a number of generalized scalar fields with arbitrary kinetic forms. These scalars have their own sound speeds respectively, so the propagations of field fluctuations are individual. Specifically, we study a model constructed by two DBI type actions. We find that the critical length scale for the freezing of perturbations corresponds to the maximum sound horizon. Moreover, if the mass term of one field is much lighter than that of the other, the entropy perturbation could be quite large and so may give rise to a growth outside sound horizon. At cubic order, we find that the non-Gaussianity of local type is possibly large when entropy perturbations are able to convert into curvature perturbations. We also calculate the non-Gaussianity of equilateral type approximately
Roles of continental mid-lithosphere discontinuity in the craton instability under variable tectonic regimes
This is the dataset for the paper "Roles of continental mid-lithosphere discontinuity in the craton instability under variable tectonic regimes"
Poly[diaquaÂ(μ2-5-carboxyÂpyridine-3-carboxylÂato-κ2 N:O 3)hemi(μ2-oxalato-κ4 O 1,O 2:O 1′,O 2′)(μ4-pyridine-3,5-dicarboxylÂato-κ4 N:O 3:O 3′:O 5)silver(I)terbium(III)]
In the title coordination polymer, [AgTb(C7H3NO4)(C7H4NO4)(C2O4)0.5(H2O)2]n, the TbIII ion is eight-coordinated by three O atoms from three different pydc (H2pydc = pyridine-3,5-dicarboxylic acid) ligands, one O atom from one Hpydc ligand, two O atoms from one oxalate ligand and two water molÂecules in a distorted square-antiÂprismatic geometry. The AgI ion is coordinated in an almost linear fashion by two pyridyl N atoms from one pydc and one Hpydc ligand and has weak interÂactions with two carboxylÂate O atoms. The carboxylÂate groups of pydc and Hpydc ligands link Tb centers, forming a one-dimensional chain. The oxalate adopts a tetraÂdentate bis-chelating coordination mode, connecting the chains into a two-dimensional layer. These layers are further assembled via [Ag(pydc)(Hpydc)] pillars and O—H⋯O and C—H⋯O hydrogen bonds into a three-dimensional coordination framework
A comprehensive review on the ferroelectric orthochromates: Synthesis, property, and application
Multiferroics represent a class of advanced materials for promising
applications and stand at the forefront of modern science for the special
feature possessing both charge polar and magnetic order. Previous studies
indicate that the family of RECrO3 (RE = rare earth) compounds is likely
another rare candidate system holding both ferroelectricity and magnetism.
However, many issues remain unsolved, casting hot disputes about whether RECrO3
is multiferroic or not. For example, an incompatibility exists between reported
structural models and observed ferroelectric behaviors, and it is not easy to
determine the spin canting degree. To address these questions, one key step is
to grow single crystals because they can provide more reliable information than
other forms of matter do. In this review, the parent and doped ferroelectric
YCrO3 compounds are comprehensively reviewed based on scientific and patent
literatures from 1954 to 2022. The materials syntheses with different methods,
including poly-, nano-, and single-crystalline samples and thin films, are
summarized. The structural, magnetic, ferroelectric and dielectric, optical,
and chemical-pressure (on Y and Cr sites by doping) dependent chemical and
physical properties and the corresponding phase diagrams, are discussed.
Diverse (potential) applications, including anti-corrosion, magnetohydrodynamic
electrode, catalyst, negative-temperature-coefficient thermistor, magnetic
refrigeration, protective coating, and solid oxide fuel cell, are present. To
conclude, we summarize general results, reached consensuses, and existing
controversies of the past nearly 69 years of intensive studies and highlight
future research opportunities and emerging challenges to address existing
issues.Comment: 69 pages, 35 figures, accepted by Coordination Chemistry Review
A meta-analysis of the efficacy of azithromycin and benzathine penicillin in early syphilis
Purpose: To systematically analyze the efficacy of azithromycin and benzathine penicillin in early syphilis, and provide guidance for diagnosis and treatment.Methods: Databases were searched for randomized controlled trials (RCTs) and control studies according to keywords, and inclusion and exclusion criteria. Related documents and meeting records were also searched manually to extract study types, basic information of study objects, intervention measurements and study results, and evaluation of the quality of the methodology used.Results: Three studies were excluded from the review. The quality evaluation was B grade, and heterogenicity was good. We adopted a fixed effect model to conduct the meta-analysis. There was no significant difference in the cure rate between azithromycin and benzathine penicillin administered for 6 months. The ORs for 3 time points were 0.96 (95% CI = 0.71, 1.29), 0.01 (95% CI = -0.05, 0.06), and 0.04 (95% CI = -0.02, 0.11; p < 0.05). There were no significant differences in the incidence of adverse events among the three studies.Conclusion: There was no apparent difference in the efficacy of azithromycin and benzathine penicillin in early syphilis. The advantages of azithromycin included good compliance, a long half-life, and a high economic benefit.Keywords: Early syphilis, Azithromycin, Benzathine penicillin, Curative effec
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