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Aims Soil fauna play a key role in the litter decomposition process in two ways; directly via fragmentation and consumption of the litter, and indirectly through changes in soil structure and the activity of microorganisms. The study aimed at better understanding how soil fauna affects the release of nutrients from litter. Methods We conducted a litter decomposition experiment using litterbags of three mesh sizes (0.01 mm, 1 mm, and 4 mm), and chemical treatments (no naphthalene; naphthalene application) to assess soil fauna effect on nutrient release in a poplar plantation in eastern China over a two-year period from Jan 2019 to Dec 2020. Results We found that the contribution of soil fauna to the mass loss of poplar leaf litter was 29% over the two-year period, and the contribution was more pronounced within the first four months. Soil macrofauna and meso-/micro- fauna contributed similarly to leaf litter mass loss, while microbial decomposition contributed the most to the decomposition process. The presence of soil fauna significantly promoted the degradation of cellulose and lignin, and accelerated the release of nitrogen at later stages of decomposition. A structural equation model revealed that higher soil fauna abundance not only promoted the litter decay rate directly, but also indirectly through modifying nitrogen and lignin contents. Conclusions Our results highlight the importance of soil fauna on cellulose and lignin degradation, and the importance of including this when simulating decomposition models for obtaining a better mechanistic understanding of forest litter decomposition.

Determining the electron neutrino mass by electron capture in 163Ho relies on an accurate understanding of the differential electron capture nuclear decay rate as a function of the distribution of the total decay energy between the neutrino and electronic excitations. The resulting spectrum is dominated by resonances due to local atomic multiplet states with core holes. Coulomb scattering between electrons couples the discrete atomic states, via Auger-Meitner decay, to final states with free electrons. The atomic multiplets are above the auto-ionisation energy, such that the delta functions representing these discrete levels turn into a superposition of Lorentzian, Mahan- and Fano-like line-shapes. We present an ab initio method to calculate nuclear decay modifications due to such processes. It includes states with multiple correlated holes in local atomic orbitals interacting with unbound Auger-Meitner electrons. A strong energy-dependent, asymmetric broadening of the resonances in good agreement with recent experiments is found. We present a detailed analysis of the mechanisms determining the final spectral line-shape and discuss both the Fano interference between different resonances, as well as the energy dependence of the Auger-Meitner Coulomb matrix elements. The latter mechanism is shown to be the dominant channel responsible for the asymmetric line-shape of the resonances in the electron capture spectrum of 163Ho.

This paper focuses on a system of the 2D magnetohydrodynamic (MHD) equations with the kinematic dissipation given by the fractional operator ( - Δ ) α and the magnetic diffusion by partial Laplacian. We are able to show that this system with any α > 0 always possesses a unique global smooth solution when the initial data is sufficiently smooth. In addition, we make a detailed study on the large-time behavior of these smooth solutions and obtain optimal large-time decay rates. Since the magnetic diffusion is only partial here, some classical tools such as the maximal regularity property for the 2D heat operator can no longer be applied. A key observation on the structure of the MHD equations allows us to get around the difficulties due to the lack of full Laplacian magnetic diffusion. The results presented here are the sharpest on the global regularity problem for the 2D MHD equations with only partial magnetic diffusion.

In this paper, we consider the Cauchy problem for an inviscid compressible Oldroyd-B model in three dimensions. The global well posedness of strong solutions and the associated time-decay estimates in Sobolev spaces are established near an equilibrium state. The vanishing of viscosity is the main challenge compared with [47] where the viscosity coefficients are included and the decay rates for the highest-order derivatives of the solutions seem not optimal. One of the main objectives of this paper is to develop some new dissipative estimates such that the smallness of the initial data and decay rates are independent of the viscosity. Moreover, we prove that the decay rates for the highest-order derivatives of the solutions are optimal, which is of independent interest. Our proof relies on Fourier theory and delicate energy method.

The rapid neutron-capture process ( r -process) is one of the main mechanisms to explain the origin of heavy elements in the universe. Although the past decades have seen great progress in understanding this process, the related nuclear physics inputs to r -process models include significant uncertainty. In this study, ten nuclear mass models, including macroscopic, macroscopic-microscopic, and microscopic models, are used to calculate the β -decay rates and neutron-capture rates of the neutron-rich isotopes for the r -process simulations occurring in three classes of astrophysical conditions. The final r -process abundances include uncertainties introduced by the nuclear mass model mainly through the variation of neutron-capture rates, whereas the uncertainties of β -decay rates make a relatively small contribution. The uncertainties in different astrophysical scenarios are also investigated, and are found to be connected to the diverse groups of nuclei produced during nucleosynthesis.

This paper solves the global well-posedness and stability problem on a special 2 1 2 -D compressible viscous non-resistive MHD system near a steady-state solution. The steady-state here consists of a positive constant density and a background magnetic field. The global solution is constructed in L p -based homogeneous Besov spaces, which allow general and highly oscillating initial velocity. The well-posedness problem studied here is extremely challenging due to the lack of the magnetic diffusion and remains open for the corresponding 3D MHD equations. Our approach exploits the enhanced dissipation and stabilizing effect resulting from the background magnetic field, a phenomenon observed in physical experiments. In addition, we obtain the solution’s optimal decay rate when the initial data is further assumed to be in a Besov space of negative index.

In this paper, we study the optimal time decay rates for the higher order spatial derivatives of solutions to a diffusive Oldroyd-B model. As pointed out in the Sect. 1.2 of Huang et al. (J Differ Equ 306:456–491, 2022), how to establish the optimal decay estimate for the highest-order spatial derivatives of the solution to this model is still an open problem. Motivated by Wang and Wen (Sci China Math 65:1199–1228, 2022), we give a positive answer to this problem via some delicate analyses on the low- and high-frequency parts of the solution.

We consider the damped wave semigroup on the tadpole graph R . We first give a meticulous spectral analysis, followed by a judicious decomposition of the resolvent’s kernel. As a consequence, and by showing that the generalized eigenfunctions form a Riesz basis of some subspace of the energy space H , we establish the exponential decay of the corresponding energy, with the optimal decay rate dictated by the spectral abscissa of the relevant operator.

We consider a porous-elastic system with localized history damping, the memory kernel decaying exponentially. We estimate the resolvent of the generator of the associated operator semigroup along the imaginary axis and then obtain an ideal polynomial decay rate of the semigroup, regardless of wave speeds. Moreover, uniform exponential stability of the semigroup is shown if either the wave speeds are equal or an additional local frictional damping is present. These results are generalizations of the previously related ones for porous-elastic or Timoshenko systems with global history damping.

Although we have gained insight into the biological and biochemical effects of natural sunlight exposure on prokaryotes, little is known about sunlight exposure on natural virus communities. To address this question, an investigation of the effects of sunlight and dark treatments on viral communities, viral production and decay rates in Kenting coastal waters was conducted. The average rate of net viral production in the sunlight and dark treatment was 0.010 and 0.018 × 10 6 viruses mL –1  h − 1 , respectively. Furthermore, averaged value for viral decay in the sunlight treatment was 0.016 × 10 6 viruses mL − 1  h − 1 , a significant decrease (ca. 60%=((0.83 − 0.33)/(0.83 × 100%)) was observed in sunlight conditions, whereas no significant changes occurred in dark conditions. The gross viral production under sunlight conditions was slightly higher, however, non-significantly higher than that in the dark treatment. As a result, we suggest that sunlight damages a large portion of the natural viral community, affecting the role viruses play in food webs.