Motivated by the current status of cosmological observations and significant tensions in the estimated values of some key parameters assuming the standard ΛCDM model, we propose a simple but radical ...phenomenological emergent dark energy model where dark energy has no effective presence in the past and emerges at later times. Theoretically, in this phenomenological dark energy model with zero degrees of freedom (similar to a ΛCDM model), one can derive that the equation of state of dark energy increases from in the past to −1 in the future. We show that by setting a hard-cut 2 lower bound prior for H0 associated with a 97.72% probability from recent local observations, this model can satisfy different combinations of cosmological observations at low and high redshifts (SNe Ia, baryon acoustic oscillation (BAO), Ly BAO, and cosmic microwave background (CMB)) substantially better than the concordance ΛCDM model with and Δ DIC ∼ −35.38. If there are no substantial systematics in SN Ia, BAO, or Planck CMB data, and assuming the reliability of current local H0 measurements, there is a very high probability that with more precise measurements of the Hubble constant our proposed phenomenological model rules out the cosmological constant with decisive statistical significance and is a strong alternative to explain the combination of different cosmological observations. This simple phenomenologically emergent dark energy model can guide theoretically motivated dark energy model building activities.
Under the mobile computing environment, a large number of convenient mobile terminals and extensive mobile network application services have been produced. The technology has been used in college ...sports teaching to optimize the management of sports teaching. In this context, this paper studies the application of the association rule algorithm and cluster analysis in basketball teaching, which will effectively promote the practice and application of the association rule algorithm and cluster analysis in college PE teaching in China. This paper studies basketball teaching in colleges and universities based on the applied explainable association rule algorithm and cluster analysis. It is concluded that the p value of positioning shooting in the basic basketball technology test between the experimental class and the control class before the experiment is 0.883, which is greater than 0.06, indicating that there is no significant difference between the experimental class and the control class before the experiment. The p value of round-trip straight dribble in the whole field is 0.735, which is greater than 0.07, indicating that there is no significant difference between the experimental class and the control class before the experiment. This teaching mode plays a significant role in cultivating beginners' learning interest and enthusiasm, preliminarily mastering movement skills and establishing solid technical concepts. With the complex emotional experience of the association rule algorithm, it is of great significance for teachers to grasp students' various emotional experiences in learning, cultivate students' team consciousness by cluster analysis, guide and dredge their negative emotions, and develop students' sense of cooperation, team spirit and democratic spirit, personal responsibility and personality.
Evidence for Emergent Dark Energy Li, Xiaolei; Shafieloo, Arman
The Astrophysical journal,
10/2020, Volume:
902, Issue:
1
Journal Article
Peer reviewed
Open access
Abstract
We introduce a generalized form of an emergent dark energy model with one degree of freedom for the dark energy sector that has the flexibility to include both the ΛCDM model as well as the ...Phenomenologically Emergent Dark Energy (PEDE) model proposed by Li & Shafieloo as two of its special limits. The free parameter for the dark energy sector, namely Δ, has a value of 0 for the Λ case and a value of 1 for the PEDE case. Fitting the introduced parametric form to Planck cosmic microwave background (CMB) data and recent
H
0
results from local observations of cepheids and supernovae, we show that the Δ = 0 associated with the ΛCDM model would fall out of the 4
σ
confidence limits of the derived posterior of the Δ parameter. Moreover,
H
0
tensions with the emergent dark energy model will be alleviated and this model can satisfy the combination of Planck CMB data and local
H
0
observations with ΔDIC = −2.88 compared with the ΛCDM model.
The improvement of regional eco-efficiency is a significant approach to achieve coordinated development of China's economic development and environmental protection, and an effective environmental ...regulation system is a crucial driver to the improvement of regional eco-efficiency. Based on the panel data of China's 30 provinces during 2000–2013, this paper divides environmental regulation into three types: command-and-control regulation, market-based regulation and voluntary regulation. STIRPAT model is employed to test the effects of these three environmental regulations on eco-efficiency in the eastern, central and western regions of China. Research results turn out that: (1) in the eastern region, market-based and voluntary environmental regulation have a positive impact on eco-efficiency improvement while command-and-control environmental regulation has no significant impact, and (2) in the central region, command-and-control and market-based environmental regulation can promote eco-efficiency more significantly compared with voluntary environmental regulation, and (3) in the western region, command-and-control environmental regulation plays a positive role in eco-efficiency improvement whilst market-based and voluntary environmental regulation have no significant impacts. These findings indicate that the effects of different types of environmental regulation on eco-efficiency apparently differ in regions. Finally, to optimize and adjust the environmental regulation tools, policy recommendations targeting different regions are concluded.
•The different effects of three types of environmental regulation on China's regional eco-efficiency are analyzed.•The effect of environmental regulation displays regional difference.•Environmental regulation has a dynamic impact on regional eco-efficiency.
The advent of immunotherapy, especially checkpoint inhibitor-based immunotherapy, has provided novel and powerful weapons against cancer. Because only a subset of cancer patients exhibit durable ...responses, further exploration of the mechanisms underlying the resistance to immunotherapy in the bulk of cancer patients is merited. Such efforts may help to identify which patients could benefit from immune checkpoint blockade. Given the existence of a great number of pathways by which cancer can escape immune surveillance, and the complexity of tumor-immune system interaction, development of various combination therapies, including those that combine with conventional therapies, would be necessary. In this review, we summarize the current understanding of the mechanisms by which resistance to checkpoint blockade immunotherapy occurs, and outline how actionable combination strategies may be derived to improve clinical outcomes for patients.
Abstract The reappearance of supernova Refsdal with detailed modeling of the lens cluster allows us to measure the time-delay distance, which serves as a powerful tool to determine the Hubble ...constant ( H 0 ). We give a cosmological-model-independent method to estimate H 0 through Gaussian process regression, using time-delay measurements from this lensed supernova in combination with supernova data from the Pantheon+ sample. Using eight mass models for the lens cluster, we infer H 0 = 64.2 − 4.3 + 4.4 km s − 1 Mpc − 1 , and using two cluster models most consistent with the observations, we infer H 0 = 66.3 − 3.6 + 3.8 km s − 1 Mpc − 1 . Our estimates of the value of H 0 are in 1 σ agreement with the results assuming a flat ΛCDM model and the uncertainties are comparable. Our constraint results on H 0 from the eight lens models and the two lens models indicate 2 σ and 1.8 σ tensions with that estimated by Supernova H0 for the Equation of State, respectively. However, our median values of H 0 from the two sets of lens models show good consistency with H 0 inferred from Planck cosmic microwave background observations assuming a ΛCDM model within 1 σ . We also find that our results for H 0 indicate 2 σ deviations and 1.7 σ deviations from the constraint results of H 0 using six time-delay quasars by H0LiCOW with the same analysis method.
Cancer immunotherapies that engage immune cells to fight against tumors are proving to be powerful weapons in combating cancer and are becoming increasingly utilized in the clinics. However, for the ...majority of patients with solid tumors, little or no progress has been seen, presumably due to lack of adequate approaches that can reprogram the local immunosuppressive tumor milieu and thus reinvigorate antitumor immunity. Tumor-associated macrophages (TAMs), which abundantly infiltrate most solid tumors, could contribute to tumor progression by stimulating proliferation, angiogenesis, metastasis, and by providing a barrier against antitumor immunity. Initial TAMs-targeting strategies have shown efficacy across therapeutic modalities and tumor types in both preclinical and clinical studies. TAMs-targeted therapeutic approaches can be roughly divided into those that deplete TAMs and those that modulate TAMs activities. We here reviewed the mechanisms by which macrophages become immunosuppressive and compromise antitumor immunity. TAMs-focused therapeutic strategies are also summarized.
Thermal energy storage system in concentrating solar power plants can guarantee sustainable and stable electricity output in case of highly unstable solar irradiation conditions. In this paper, the ...lumped parameter method is used to develop the models of different thermal energy storage systems. In order to improve the reliability as well as the prediction accuracy of developed models, the charging/discharging process is firstly simulated, and then the dynamic characteristics of thermal energy storage systems are fully tested by imposing 15% step disturbance of mass flow. The results show that the charging/discharging characteristics of the three different thermal energy storage systems are almost the same, which have little to do with the storage mediums used in the systems. Besides, for the representative 1MWe solar parabolic trough power plant, a 15% step up disturbance of oil mass flow will result in a small increase (1.8% and 1.3% respectively) on the outlet temperature of oil and molten salt. On the other side, a 15% step down disturbance of oil mass flow will lead a 2.7% and 2.2% decrease on the outlet temperature of oil and molten salt respectively. In order to verify the validity of the proposed models, the simulation results are compared with both the design points and representative experimental data from the 1MWe solar parabolic trough power plant. The results show that the maximum relative error is not more than 1% when comparing with the design points and the maximum relative error is not more than 12% when comparing with the representative experimental data. Conclusions of this paper are good references for system design, control and commissioning of concentrating solar power plants.
•Thermal energy storage can provide sustainable and stable electricity output.•Lumped parameter method is used to build the model of thermal energy storage.•The dynamic characteristics are tested by a 15% step disturbance of mass flow.•A 15% step-up will result in a 1.3% increase in molten salt outlet temperature.•A 15% step down will result in a 2.2% decrease in molten salt outlet temperature.
Cerebral ischemia is the most common type of neuronal injury and is characterized by a reduction in the function and number of hippocampal neurons. Carvacrol has a significant neuroprotective effect ...in cerebral ischemia. However, the mechanisms by which carvacrol affects cerebral ischemia, especially with respect to the regulation of neuronal damage by iron levels, have never been systematically studied. This study aimed to reveal the mechanisms by which carvacrol protects against hippocampal neuron impairment after ischemic stroke in gerbils.
The Morris water maze test was performed to evaluate learning and memory impairments. Iron ion content and oxidative stress index were detected by the kit. MTT assay was performed to assess the cell viability. The morphology and molecular characteristics were detected by electron micrographs and western blot.
In the present study, we demonstrated the neuroprotective effects of carvacrol in vivo and in vitro. The Morris water maze test showed that the learning and memory abilities of the gerbils treated with carvacrol were significantly improved. Lipid peroxide injury was evaluated by measuring the levels of lipid peroxide biomarkers; the results indicated that carvacrol decreased the level of lipid peroxide in ischemic gerbil brain tissue. Histopathological examinations and western blotting were performed to evaluate injury in neurons, and carvacrol reduced cell death. Moreover, ferroptosis in the hippocampus was evaluated by measuring the levels of proteins involved in this iron-dependent form of regulated cell death. These results indicated that carvacrol reduced cell death and that carvacrol inhibited ferroptosis by increasing the expression of glutathione peroxidase 4(GPx4). This study showed that carvacrol may be a valuable drug for treating cerebral ischemia.
Carvacrol provides protection for hippocampal neurons against I/R in gerbils by inhibiting ferroptosis through increasing the expression of GPx4.
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Human glycans are primarily composed of nine common sugar building blocks. On the other hand, several hundred monosaccharides have been discovered in bacteria and most of them are not readily ...available. The ability to access these rare sugars and the corresponding glycoconjugates can facilitate the studies of various fundamentally important biological processes in bacteria, including interactions between microbiota and the human host. Many rare sugars also exist in a variety of natural products and pharmaceutical reagents with significant biological activities. Although several methods have been developed for the synthesis of rare monosaccharides, most of them involve lengthy steps. Herein, we report an efficient and general strategy that can provide access to rare sugars from commercially available common monosaccharides via a one-step Ru(II)-catalyzed and boron-mediated selective epimerization of 1,2-trans-diols to 1,2-cis-diols. The formation of boronate esters drives the equilibrium toward 1,2-cis-diol products, which can be immediately used for further selective functionalization and glycosylation. The utility of this strategy was demonstrated by the efficient construction of glycoside skeletons in natural products or bioactive compounds.
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