Oscillons are massive, long-lived, localized excitations of a scalar field. We show that in a class of well-motivated single-field models, inflation is followed by self resonance, leading to copious oscillon generation and a lengthy period of oscillon domination. These models are characterized by an inflaton potential which has a quadratic minimum and is shallower than quadratic away from the minimum. This set includes both string monodromy models and a class of supergravity inspired scenarios and is in good agreement with the current central values of the concordance cosmology parameters. We assume that the inflaton is weakly coupled to other fields so as not to quickly drain energy from the oscillons or prevent them from forming. An oscillon-dominated universe has a greatly enhanced primordial power spectrum on very small scales relative to that seen with a quadratic potential, possibly leading to novel gravitational effects in the early Universe.
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http://dx.doi.org/10.1103/PhysRevLett.108.241302 | DOI Listing |
Heliyon
December 2024
Department of Plant and Soil Sciences, 117 Dorman Hall, Box 9555, Mississippi State University, Mississippi State, MS, 39762, USA.
Temperature is a fundamental factor influencing the processes of seed germination. Investigating the response of carinata to thermal stress and establishing a dependable and efficient method for screening thermotolerance will enhance breeding programs and model applications. We assessed the response of 12 carinata genotypes to a range of eight temperatures, spanning from 8 to 37 °C, throughout the germination process.
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January 2025
College of Mechanical and Electrical Engineering, Shihezi University, Shihezi, 832003, China.
In response to the rotary ploughing equipment in the stubble land to implement protective operations, the stubble is large in number and strong in toughness, not easy to crush, resulting in rotary ploughing equipment to produce entanglement and increased resistance to rotary ploughing and other issues. In this study, researchers designed a bionic rotary tillage blade (B-RTB) based on the bionic structural equations of the Marmota claw. A straw-soil complex shear performance test was conducted to investigate the effect of straw on soil shear strength.
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December 2024
School of Mechanical Engineering, Zhejiang Sci-Tech University, Hangzhou, Zhejiang, China.
To address the problems of the labeling curved surfaces vegetable with long label, such as the label wrinkled and the easy detachment, a cam-elliptical gear combined labeling mechanism with an improved hypocycloid trajectory is proposed. Provide the process of the mechanism, and establish a kinematic model of the mechanism. In order to improve the motion performances of the cam-elliptical gear combined labeling mechanism and avoid labels damage, the NSGA-II algorithm is used to optimize the parameters of the mechanism, resulting in 80 sets of Pareto solutions.
View Article and Find Full Text PDFMagn Reson Med
December 2024
Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada.
Purpose: The purpose of this study was to investigate microstructural changes in the aging adult prostate by comparing the effects of varying diffusion times using diffusion MRI, and to provide an age-related benchmark for future prostate cancer studies.
Methods: The prostates of normal male volunteers (n = 70, 19-69 years) were scanned at 3 T with an oscillating gradient spin echo (OGSE: 6 ms), pulsed gradient spin echo (PGSE: 40 ms) and pulsed gradient stimulated echo (PGSTE: 100 ms), and anatomical T-weighted image. Volume and mean diffusivity (MD) were measured in the peripheral (PZ) and transition zones (TZ), which were assessed versus age.
ISA Trans
December 2024
National Engineering Laboratory of Integrated Transportation Big Data Application Technology, Southwest Jiaotong University, China. Electronic address:
In this paper, we propose a suboptimal distributed cooperative control scheme for the continuous-time linear multi-agent system (MAS) with a specified global quadratic cost functional over both undirected and directed graph scenarios. For undirected graphs, we first derive the cost functional for a given strictly linear feedback distributed protocol. It is shown that the cost functional is upper bounded by a quadratic form of the MAS's initial state, and the minimum upper bound can be derived by solving a parametric algebraic Riccati equation (PARE) depends solely on the algebraic connectivity of the graph and is independent of the largest eigenvalue compared with the existing work.
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