Future Climate Change Will Have a Positive Effect on Populus Davidiana in China

Since climate change significantly affects global biodiversity, a reasonable assessment of the vulnerability of species in response to climate change is crucial for conservation. Most existing methods estimate the impact of climate change on the vulnerability of species by projecting the change of a species’ distribution range. This single-component evaluation ignores the impact of other components on vulnerability. In this study, Populus davidiana (David’s aspen), a tree species widely used in afforestation projects, was selected as the research subject under four future climate change scenarios (representative concentration pathway (RCP)2.6, RCP4.5, RCP6.0, and RCP8.5). Exposure components of range change as well as the degree of fragmentation, degree of human disturbance, and degree of protection were considered simultaneously. Then, a multicomponent vulnerability index was established to assess the effect of future climate change on the vulnerability of P. davidiana in China. The results show that the distribution range of P. davidiana will expand to the northwest of China under future climate change scenarios, which will lead to an increased degree of protection and a decreased degree of human disturbance, and hardly any change in the degree of fragmentation. The multicomponent vulnerability index values of P. davidiana under the four emission scenarios are all positive by 2070, ranging from 14.05 to 38.18, which fully indicates that future climate change will be conducive to the survival of P. davidiana. This study provides a reference for the development of conservation strategies for the species as well as a methodological case study for multicomponent assessment of species vulnerability to future climate change

Visualizing the elongated vortices in γ\gamma-Ga nanostrips

We study the magnetic response of superconducting $\gamma$-Ga via low temperature scanning tunneling microscopy and spectroscopy. The magnetic vortex cores rely substantially on the Ga geometry, and exhibit an unexpectedly-large axial elongation with aspect ratio up to 40 in rectangular Ga nano-strips (width $l$ $<$ 100 nm). This is in stark contrast with the isotropic circular vortex core in a larger round-shaped Ga island. We suggest that the unusual elongated vortices in Ga nanostrips originate from geometric confinement effect probably via the strong repulsive interaction between the vortices and Meissner screening currents at the sample edge. Our finding provides novel conceptual insights into the geometrical confinement effect on magnetic vortices and forms the basis for the technological applications of superconductors.Comment: published in Phys. Rev. B as a Rapid Communicatio

Multidimensional Resource Fragmentation-Aware Virtual Network Embedding in MEC Systems Interconnected by Metro Optical Networks

The increasing demand for diverse emerging applications has resulted in the interconnection of multi-access edge computing (MEC) systems via metro optical networks. To cater to these diverse applications, network slicing has become a popular tool for creating specialized virtual networks. However, resource fragmentation caused by uneven utilization of multidimensional resources can lead to reduced utilization of limited edge resources. To tackle this issue, this paper focuses on addressing the multidimensional resource fragmentation problem in virtual network embedding (VNE) in MEC systems with the aim of maximizing the profit of an infrastructure provider (InP). The VNE problem in MEC systems is transformed into a bilevel optimization problem, taking into account the interdependence between virtual node embedding (VNoE) and virtual link embedding (VLiE). To solve this problem, we propose a nested bilevel optimization approach named BiVNE. The VNoE is solved using the ant colony system (ACS) in the upper level, while the VLiE is solved using a combination of a shortest path algorithm and an exact-fit spectrum slot allocation method in the lower level. Evaluation results show that the BiVNE algorithm can effectively enhance the profit of the InP by increasing the acceptance ratio and avoiding resource fragmentation simultaneously

Genetic diversity and population structure of Sepiella japonica (Mollusca: Cephalopoda: Decapoda) inferred by 16S rDNA variations

In order to describe the genetic diversity and phylogenetic relationship of five populations of cuttlefish (Sepiella japonica) along with China's coasts, partial 16S rDNA (510 bp in length) was amplified from 110 individuals. The five populations of cuttlefish inhabit Yellow Sea, East China Sea and South China Sea. In total, six haplotypes were identified and formed only one clade. Among the six haplotypes, one was shared by all populations, three appeared only in a single population, two appeared in two or three populations. Pair-wise FST were not proportional to the geographical distances. Haplotype diversity and nucleotide diversity were low, 0.3866 ± 0.067 and 0.00120 ± 0.00081 respectively. Among the five populations, Zhoushan population exhibited the highest genetic diversity which was suggested as the better select of germplasm resources for the reproduction and releasing of S. japonica

Age Determination of LAMOST Red Giant Branch stars based on the Gradient Boosting Decision Tree method

In this study we estimate the stellar ages of LAMOST DR5 Red Giant Branch (RGB) stars based on the Gradient Boosting Decision Tree algorithm (GBDT). We used 2088 RGB stars extracted from the APOKASC-2 astero-seismological catalog as training data-set. After selecting the parameters highly correlated with age using GBDT, we apply the same GBDT method to the new catalog of more than 690,000 stars classified as RGB stars. The test data-set shows that the median relative error is around 0.3 $\%$ for the method. We also compare the predicted ages of RGB stars with other studies (e.g. based on APOGEE), and find that they are almost consistent. The final uncertainty is about 14 $\%$ compared to open clusters' ages. Then we present the spatial distribution of the RGB sample having an age determination and discuss some systematics. All these diagnostics show that one can apply the GBDT method to other stellar samples to estimate atmospheric parameters and age.Comment: 17 pages, 16 figure

Complete two-loop electroweak corrections to e+e−→HZe^+e^-\rightarrow HZ

We compute the complete two-loop electroweak corrections to the Higgsstralung process $e^+e^-\rightarrow HZ$ at the future Higgs factory. The Feynman integrals involved in the computation are decomposed into linear combinations of a minimal set of master integrals taking advantage of the recent developments of integral reduction techniques. The master integrals are then evaluated by differential equations with boundary conditions provided by the auxiliary mass flow method. Our final result for given $\sqrt{s}$ is expressed as a piecewise function defined by several deeply expanded power series, which has high precision and can be further manipulated efficiently. Our calculation presents the first complete two-loop electroweak corrections for processes with four external particles.Comment: 5 pages, 2 figures. arXiv admin note: text overlap with arXiv:2209.1425