119 research outputs found
Constraints on the Spacetime Variation of the Fine-structure Constant Using DESI Emission-line Galaxies
No full textLinhua Jiang et al.The DESI CollaborationWe present strong constraints on the spacetime variation of the fine-structure constant α using the Dark Energy Spectroscopic Instrument (DESI). In this pilot work, we utilize ∼110,000 galaxies with strong and narrow [O iii] λ λ4959, 5007 emission lines to measure the relative variation Δα/α in space and time. The [O iii] doublet is arguably the best choice for this purpose owing to its wide wavelength separation between the two lines and its strong emission in many galaxies. Our galaxy sample spans a redshift range of 0 < z < 0.95, covering half of all cosmic time. We divide the sample into subsamples in 10 redshift bins (Δz = 0.1), and calculate Δα/α for the individual subsamples. The uncertainties of the measured Δα/α are roughly between 2 × 10−6 and 2 × 10−5. We find an apparent α variation with redshift at a level of Δα/α = (2-3) × 10−5. This is highly likely to be caused by systematics associated with wavelength calibration, since such small systematics can be caused by a wavelength distortion of 0.002-0.003 Å, which is beyond the accuracy that the current DESI data can achieve. We refine the wavelength calibration using sky lines for a small fraction of the galaxies, but this does not change our main results. We further probe the spatial variation of α in small redshift ranges, and do not find obvious, large-scale structures in the spatial distribution of Δα/α. As DESI is ongoing, we will include more galaxies, and by improving the wavelength calibration, we expect to obtain a better constraint that is comparable to the strongest current constraint.We acknowledge support from the National Science Foundation of China (12225301) and the National Key R&D Program of China (2022YFF0503401).
This research used data obtained with the Dark Energy Spectroscopic Instrument (DESI). DESI construction and operations is managed by the Lawrence Berkeley National Laboratory. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High-Energy Physics, under Contract No. DE-AC02-05CH11231, and by the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility under the same contract. Additional support for DESI was provided by the U.S. National Science Foundation (NSF), Division of Astronomical Sciences under Contract No. AST-0950945 to the NSF's National Optical-Infrared Astronomy Research Laboratory; the Science and Technology Facilities Council of the United Kingdom; the Gordon and Betty Moore Foundation; the Heising-Simons Foundation; the French Alternative Energies and Atomic Energy Commission (CEA); the National Council of Science and Technology of Mexico (CONACYT); the Ministry of Science and Innovation of Spain (MICINN), and by the DESI Member Institutions: www.desi.lbl.gov/collaborating-institutions. The DESI collaboration is honored to be permitted to conduct scientific research on Iolkam Du'ag (Kitt Peak), a mountain with particular significance to the Tohono O'odham Nation. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the U.S. National Science Foundation, the U.S. Department of Energy, or any of the listed funding agencies.Peer reviewe
Super resolution reconstruction based on adaptive sparse domain and total variation regularization of wavelet transform
No full textInverse radiation problem in one-dimensional semitransparent plane-parallel media with opaque and specularly reflecting boundaries
No full textFirst-Principles Study on Electronic Band Structure and Optical Constants of Synthesized Si3Al(AsxP1-x) Alloys
No full textInverse radiation problem of temperature field in three-dimensional rectangular furnaces
No full textTrust to test translation practices: A case study of Shanghai, China
No full textTrust is important in public health communication to culturally and linguistically diverse (CALD) communities during pandemics. This empirical research, using quantitative data from 107 foreign nationals at a university in Shanghai, probes into how trust varied in official translation services (OTS) and non-official translation services (NOTS) during COVID-19. Statistical analysis was carried out by IBM SPSS Statistics 26 and it was found that (1) NOTS which are more frequently used are more trusted compared with OTS; (2) NOTS are uncorrelated with demographics while OTS are correlated with demographics, among which education and trust in OTS suggest a linear positive relationship (Sig. = 0.003, β = 0.467), whereas age and trust in OTS suggest a linear negative relationship (Sig. = 0.027, β = −0.348); (3) there is a positive relationship between the frequency of using services and trust, i.e., higher frequency implies higher trust. The findings of this case study can have implications for policy makers and the representatives of CALD communities.Quantum Circuit Architectures and Technolog
An Applied Research on the Compound Air Conditioning System of Ground Source Direct Cooling System and Water Storage Tank System
No full textAbstractEnergy is an important material basis for China's economic and social development. The green building with the rule of energy saving and environmental protection and the reasonable and efficient air-conditioning systems arises at the historic moment. A Compound Air Conditioning System (CACS) of Ground Source Direct Cooling (GSDC) system and Water Storage Tank System (WSTS) is applied in an clod area and in details presented. The monitored data shows that the average operating cost of the air conditioning each year is lower than 10 Chinese yuan/m2. Therefore, this CACS system has a great potentiality in the demand of building energy saving in the cold areas
Numerical Evaluation of the Indoor Environment in a Room with Capillary Radiation Air Conditioning System
No full textAbstractNumerical simulation has been conducted in a conference room with capillary radiation air conditioning system in Jinan. The influence of the different supply air speed on the indoor temperature field, velocity field, air age, PMV and PPD have been studied. It is found that the indoor thermal comfort level is the highest when supply air velocity is in the range of 1.75 to 2 m/s
Increased Nitrosoglutathione Reductase Activity in Hypoxic Pulmonary Hypertension in Mice
No full textAltered S-nitrosothiols (RSNO) signaling is linked to pulmonary hypertension. Recent studies have shown that S-nitrosoglutathione (GSNO) reductase (GSNOR) catalyzes the degradation of GSNO and indirectly regulates the level of RSNO in vivo. Our present study tested the hypothesis that chronic hypoxia causes pulmonary hypertension, in part, by the change of GSNOR activity that contributes to the depletion of RSNO. Male mice were exposed to normobaric hypoxia in a ventilated chamber for 1 to 21 days or normoxia for 21 days. Right ventricular systolic pressure, right ventricle hypertrophy, and the number and media thickness of muscular pulmonary vessels increased significantly after 21 days of hypoxic exposure. Hypoxia induced the overexpression of endothelial nitric oxide synthase and inducible nitric oxide synthase. The mRNA expression of GSNOR decreased on day 1 of hypoxic exposure, but increased significantly on day 7 compared with the normoxic group. The protein expression of GSNOR increased significantly in the lung tissue after 7 days of hypoxic exposure and its enzymatic activities also increased. Both the ratios of glutathione to glutathione disulfide and nitrate to nitrite were significantly lower in the hypoxic groups than in the normoxic controls. The results suggest an increased GSNOR activity interfered with the metabolism of RSNO in mice with hypoxic pulmonary hypertension. An imbalanced of redox status is associated with the pathogenesis of hypoxic pulmonary hypertension. Keywords:: hypoxia, S-nitrosoglutathione reductase, endothelial nitric oxide synthase, glutathione and glutathione disulfid
Regulatory effect of lactulose on intestinal flora and serum metabolites in colitis mice: In vitro and in vivo evaluation
No full textLactulose is a common component in foods. However, the effect of lactulose on intestinal flora and overall metabolic levels remains unclear. Therefore, this study aims to explore the regulative role of lactulose on intestinal flora and serum metabolites via in vitro simulated colonic fermentation model and in vivo colitis mouse model. The results showed that lactulose significantly enriched beneficial bacteria including Dubosiella and Bifidobacterium, and reduced pathogenic bacteria such as Fusobacterium. Moreover, lactulose significantly inhibited dextran sodium sulfate-induced body weight loss, colon shortening, colonic inflammatory infiltration, and pro-inflammatory cytokines IL-6, TNF-α, IL-17, and IL-1β. Lactulose significantly affected serum metabolome in colitis mice and total 24 metabolites representing a high inter-group difference were obtained. Correlation analysis revealed that the changes in serum metabolites were closely associated with the role of intestinal flora, and thus affected phenotypic indicators. Our study provides a reference for nutritional characteristics and application scenarios of dietary lactulose
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