Dark viscous fluid described by a unified equation of state in cosmology

We generalize the $\Lambda$CDM model by introducing a unified EOS to describe the Universe contents modeled as dark viscous fluid, motivated by the fact that a single constant equation of state (EOS) $p=-p_0$ ($p_0>0$) reproduces the $\Lambda$CDM model exactly. This EOS describes the perfect fluid term, the dissipative effect, and the cosmological constant in a unique framework and the Friedmann equations can be analytically solved. Especially, we find a relation between the EOS parameter and the renormalizable condition of a scalar field. We develop a completely numerical method to perform a $\chi^2$ minimization to constrain the parameters in a cosmological model directly from the Friedmann equations, and employ the SNe data with the parameter $\mathcal{A}$ measured from the SDSS data to constrain our model. The result indicates that the dissipative effect is rather small in the late-time Universe.Comment: 4 pages, 2 figures. v2: new materials added. v3: matches the version to appear in IJMP

Erosion-induced massive organic carbon burial and carbon emission in the Yellow River basin, China

Soil erosion and terrestrial deposition of soil organic carbon (SOC) can potentially play a significant role in global carbon cycling. Assessing the redistribution of SOC during erosion and subsequent transport and burial is of critical importance. Using hydrological records of soil erosion and sediment load, and compiled organic carbon (OC) data, estimates of the eroded soils and OC induced by water in the Yellow River basin during the period 1950–2010 were assembled. The Yellow River basin has experienced intense soil erosion due to combined impact of natural process and human activity. Over the period, 134.2 ± 24.7 Gt of soils and 1.07 ± 0.15 Gt of OC have been eroded from hillslopes based on a soil erosion rate of 1.7–2.5 Gt yr⁻¹. Approximately 63% of the eroded soils were deposited in the river system, while only 37% were discharged into the ocean. For the OC budget, approximately 0.53 ± 0.21 Gt (49.5%) was buried in the river system, 0.25 ± 0.14 Gt (23.5%) was delivered into the ocean, and the remaining 0.289 ± 0.294 Gt (27%) was decomposed during the erosion and transport processes. This validates the commonly held assumption that 20–40% of the eroded OC would be oxidized after erosion. Erosion-induced OC redistribution on the landscape likely represented a carbon source, although a large proportion of OC was buried. In addition, about half of the terrestrially redeposited OC (49.4%) was buried behind dams, revealing the importance of dam trapping in sequestering the eroded OC. Although several uncertainties need to be better constrained, the obtained budgetary results provide a means of assessing the redistribution of the eroded OC within the Yellow River basin. Human activities have significantly altered its redistribution pattern over the past decades

Reconstruction of 5D5D Cosmological Models From Equation of State of Dark Energy

We consider a class of five-dimensional cosmological solutions which contains two arbitrary function $\mu(t)$ and $\nu(t)$. We found that the arbitrary function $\mu(t)$ contained in the solutions can be rewritten in terms of the redshift $z$ as a new arbitrary function $f(z)$. We further showed that this new arbitrary function $f(z)$ could be solved out for four known parameterized equations of state of dark energy. Then the $5D$ models can be reconstructed and the evolution of the density and deceleration parameters of the universe can be determined.Comment: 10 pages, 4 eps figures, ws-ijmpd.cls styl

Hydrogen Sulfide Mitigates Myocardial Infarction via Promotion of Mitochondrial Biogenesis-Dependent M2 Polarization of Macrophages.

Published onlineJOURNAL ARTICLEAIMS: Macrophages are of key importance for tissue repair after myocardial infarction (MI). Hydrogen sulfide (H2S) has been shown to exert cardioprotective effects in MI. However, the mechanisms by which H2S modulates cardiac remodeling and repair post-MI remain to be clarified. RESULTS: In our current study, we showed H2S supplementation ameliorated pathological remodeling and dysfunction post-MI in WT and CSE-KO mice, resulting in decreased infarct size and mortality, accompanied by an increase in the number of M2-polarized macrophages at the early stage of MI. Strikingly, adoptive transfer of NaHS-treated (BMMs) into WT and CSE-KO mice with depleted macrophages also ameliorated MI-induced cardiac functional deterioration. Further mechanistic studies demonstrated that NaHS-induced M2 polarization was achieved by enhanced mitochondrial biogenesis and fatty acid oxidation (FAO). INNOVATION AND CONCLUSION: Our study shows, for the first time, that H2S may have the potential as a therapeutic agent for MI via promotion of M2 macrophage polarization.This work was funded by the Key Program of National Nature Science Foundation of China (No.81330080) and the Key Program of Shanghai Committee of Science and Technology in China (No. 14JC1401100)

Chaotic Properties of Subshifts Generated by a Non-Periodic Recurrent Orbit

The chaotic properties of some subshift maps are investigated. These subshifts are the orbit closures of certain non-periodic recurrent points of a shift map. We first provide a review of basic concepts for dynamics of continuous maps in metric spaces. These concepts include nonwandering point, recurrent point, eventually periodic point, scrambled set, sensitive dependence on initial conditions, Robinson chaos, and topological entropy. Next we review the notion of shift maps and subshifts. Then we show that the one-sided subshifts generated by a non-periodic recurrent point are chaotic in the sense of Robinson. Moreover, we show that such a subshift has an infinite scrambled set if it has a periodic point. Finally, we give some examples and discuss the topological entropy of these subshifts, and present two open problems on the dynamics of subshifts

Effects of livestock grazing on soil nitrogen mineralization on Hulunber meadow steppe, China

Soil nitrogen (N) cycling is an important factor in terrestrial ecosystems, including grasslands. Understanding the effects of grazing on nitrogen cycling in grassland ecosystems is critical for better management and for improving knowledge of the mechanisms underlying grassland degradation and can provide basic information for sustainable development in grassland ecosystems. In this study, in situ incubation in intact soil cores was used to measure seasonal changes in soil nitrogen mineralization and nitrification in the meadow steppe of the Hulunber grasslands of northeastern China. Soil plots were subjected to varying intensities of cattle grazing, and soil characteristics including several aspects of the nitrogen cycle were analysed. The findings demonstrate that soil inorganic N pools and nitrogen mineralization peaked in August and that moderate grazing intensity produced higher seasonal mean net N mineralization (Amin); net nitrogen mineralization rate (Rmin); net ammonification rate (Ramm) and net nitrification rate (Rnit). Seasonal mean net mineralization rate was increased by 6–15% in the lightly and moderately grazed plots (0.34–0.46 AU cow/ha) and by 4–5% in the heavily grazed plots (0.69–0.92 AU cow/ha). Also it was found that soil moisture was significantly positively correlated with inorganic N, Amin, Ramm and Rmin and significantly negatively correlated with Rnit, while soil temperature exhibited the opposite effect. The obtained results demonstrated net nitrogen mineralization and ammonium rates, which were strongly linked to grazing intensity, soil temperature and soil moisture