nuclear density
Recently Published Documents


TOTAL DOCUMENTS

294
(FIVE YEARS 42)

H-INDEX

29
(FIVE YEARS 2)

2022 ◽  
Author(s):  
Rong An ◽  
Shisheng Zhang ◽  
Li-Sheng Geng ◽  
Feng-Shou 张丰收 Zhang

Abstract We apply the recently proposed RMF(BCS)* ansatz to study the charge radii of the potassium isotopic chain up to $^{52}$K. It is shown that the experimental data can be reproduced rather well, qualitatively similar to the Fayans nuclear density functional theory, but with a slightly better description of the odd-even staggerings (OES). Nonetheless, both methods fail for $^{50}$K and to a lesser extent for $^{48,52}$K. It is shown that if these nuclei are deformed with a $\beta_{20}\approx-0.2$, then one can obtain results consistent with experiments for both charge radii and spin-parities. We argue that beyond mean field studies are needed to properly describe the charge radii of these three nuclei, particularly for $^{50}$K.


2021 ◽  
Author(s):  
Silvia Cellone Trevelin ◽  
Suzanne Pickering ◽  
Katrina Todd ◽  
Cynthia Bishop ◽  
Michael Pitcher ◽  
...  

Confirmed SARS-coronavirus-2 infection with gastrointestinal symptoms and changes in microbiota associated with coronavirus disease 2019 (COVID-19) severity have been previously reported, but the disease impact on the architecture and cellularity of ileal Peyers patches (PP) remains unknown. Here we analysed post-mortem tissues from throughout the gastrointestinal (GI) tract of patients who died with COVID-19. When virus was detected by PCR in the GI tract, immunohistochemistry identified virus in epithelium and lamina propria macrophages, but not in lymphoid tissues. Immunohistochemistry and imaging mass cytometry (IMC) analysis of ileal PP revealed depletion of germinal centres (GC), disruption of B cell/T cell zonation and decreased potential B and T cell interaction and lower nuclear density in COVID-19 patients. This occurred independent of the local viral levels. The changes in PP demonstrate that the ability to mount an intestinal immune response is compromised in severe COVID-19, which could contribute to observed dysbiosis.


2021 ◽  
Vol 54 (5) ◽  
Author(s):  
Maykel Manawan ◽  
Evvy Kartini ◽  
Maxim Avdeev

Li3PO4 is known to demonstrate Li+ ionic conductivity, making it a good candidate for solid electrolytes in all-solid batteries. Understanding the crystal structure and its connection to Li+ diffusion is essential for further rational doping to improve the ionic transport mechanism. The purpose of this study is to investigate this mechanism using anisotropic displacement parameters (ADPs), nuclear density distribution and bond valence mapping. In situ neutron powder diffraction experiments have been performed using the high-resolution powder diffractometer ECHIDNA at the OPAL reactor, Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, NSW, Australia. The ADPs and nuclear density distribution were determined from the analysis of neutron diffraction data using the Rietveld method, whereas the bond valence map was calculated from the refined structure. The crystal structure remained unchanged as the temperature was increased (3, 100, 300 and 400 K). However, the ADPs show a greater increase in anisotropy in the a and b axes compared with the c axis, indicating the tendency of the ionic movement. By combining nuclear density distribution and bond valence mapping, the most likely lithium-ion diffusion in the crystal structure can be visualized.


2021 ◽  
Author(s):  
Zhuangzhuang Wang ◽  
Mengning Yang ◽  
Yangfan Lyu ◽  
Kairun Chen ◽  
Qicheng Tang

2021 ◽  
Vol 22 (13) ◽  
pp. 6983
Author(s):  
Lara Caetano Rocha ◽  
Gabriela Klein Barbosa ◽  
Jurandyr Pimentel Neto ◽  
Carolina dos Santos Jacob ◽  
Andreas B. Knudsen ◽  
...  

The myotendinous junction (MTJ) is the muscle-tendon interface and constitutes an integrated mechanical unit to force transmission. Joint immobilization promotes muscle atrophy via disuse, while physical exercise can be used as an adaptative stimulus. In this study, we aimed to investigate the components of the MTJ and their adaptations and the associated elements triggered with aquatic training after joint immobilization. Forty-four male Wistar rats were divided into sedentary (SD), aquatic training (AT), immobilization (IM), and immobilization/aquatic training (IMAT) groups. The samples were processed to measure fiber area, nuclear fractal dimension, MTJ nuclear density, identification of telocytes, sarcomeres, and MTJ perimeter length. In the AT group, the maintenance of ultrastructure and elements in the MTJ region were observed; the IM group presented muscle atrophy effects with reduced MTJ perimeter; the IMAT group demonstrated that aquatic training after joint immobilization promotes benefits in the muscle fiber area and fractal dimension, in the MTJ region shows longer sarcomeres and MTJ perimeter. We identified the presence of telocytes in the MTJ region in all experimental groups. We concluded that aquatic training is an effective rehabilitation method after joint immobilization due to reduced muscle atrophy and regeneration effects on MTJ in rats.


2021 ◽  
pp. 2130017
Author(s):  
Ariel Zhitnitsky

We review a testable, the axion quark nugget (AQN) model outside of the standard WIMP paradigm. The model was originally invented to explain the observed similarity between the dark and the visible components, [Formula: see text], in a natural way as both types of matter are formed during the same QCD transition and proportional to the same dimensional fundamental parameter of the system, [Formula: see text]. In this framework, the baryogenesis is actually a charge segregation (rather than charge generation) process which is operational due to the [Formula: see text]-odd axion field, while the global baryon number of the Universe remains zero. The nuggets and anti-nuggets are strongly interacting but macroscopically large objects with approximately nuclear density. We overview several specific recent applications of this framework. First, we discuss the “solar corona mystery” when the so-called nanoflares are identified with the AQN annihilation events in corona. Secondly, we review a proposal that the recently observed by the Telescope Array puzzling events is a result of the annihilation events of the AQNs under thunderstorm. Finally, we overview a broadband strategy which could lead to the discovery the AQN-induced axions representing the heart of the construction.


2021 ◽  
Author(s):  
Nazanin Jahani ◽  
◽  
Joaquín Ambía ◽  
Kristian Fossum ◽  
Sergey Alyaev ◽  
...  

The cost of drilling wells on the Norwegian Continen-tal Shelf are extremely high, and hydrocarbon reservoirs are often located in spatially complex rock formations. Optimized well placement with real-time geosteering is crucial to efficiently produce from such reservoirs and reduce exploration and development costs. Geosteering is commonly assisted by repeated formation evaluation based on the interpretation of well logs while drilling. Thus, reliable computationally efficient and robust work-flows that can interpret well logs and capture uncertain-ties in real time are necessary for successful well place-ment. We present a formation evaluation workflow for geosteering that implements an iterative version of an ensemble-based method, namely the approximate Leven-berg Marquardt form of the Ensemble Randomized Max-imum Likelihood (LM-EnRML). The workflow jointly estimates the petrophysical and geological model param-eters and their uncertainties. In this paper the demon-strate joint estimation of layer-by-layer water saturation, porosity, and layer-boundary locations and inference of layers’ resistivities and densities. The parameters are estimated by minimizing the statistical misfit between the simulated and the observed measurements for several logs on different scales simultaneously (i.e., shallow-sensing nuclear density and shallow to extra-deep EM logs). Numerical experiments performed on a synthetic exam-ple verified that the iterative ensemble-based method can estimate multiple petrophysical parameters and decrease their uncertainties in a fraction of time compared to clas-sical Monte Carlo methods. Extra-deep EM measure-ments are known to provide the best reliable informa-tion for geosteering, and we show that they can be in-terpreted within the proposed workflow. However, we also observe that the parameter uncertainties noticeably decrease when deep-sensing EM logs are combined with shallow sensing nuclear density logs. Importantly the es-timation quality increases not only in the proximity of the shallow tool but also extends to the look ahead of the extra-deep EM capabilities. We specifically quantify how shallow data can lead to significant uncertainty re-duction of the boundary positions ahead of bit, which is crucial for geosteering decisions and reservoir mapping.


Sign in / Sign up

Export Citation Format

Share Document