Phylogenetic Analysis of Algal Symbionts Associated with Four North American Amphibian Egg Masses

Egg masses of the yellow-spotted salamander Ambystoma maculatum form an association with the green alga “Oophila amblystomatis” (Lambert ex Wille), which, in addition to growing within individual egg capsules, has recently been reported to invade embryonic tissues and cells. The binomial O. amblystomatis refers to the algae that occur in A. maculatum egg capsules, but it is unknown whether this population of symbionts constitutes one or several different algal taxa. Moreover, it is unknown whether egg masses across the geographic range of A. maculatum, or other amphibians, associate with one or multiple algal taxa. To address these questions, we conducted a phylogeographic study of algae sampled from egg capsules of A. maculatum, its allopatric congener A. gracile, and two frogs: Lithobates sylvatica and L. aurora. All of these North American amphibians form associations with algae in their egg capsules. We sampled algae from egg capsules of these four amphibians from localities across North America, established representative algal cultures, and amplified and sequenced a region of 18S rDNA for phylogenetic analysis. Our combined analysis shows that symbiotic algae found in egg masses of four North American amphibians are closely related to each other, and form a well-supported clade that also contains three strains of free-living chlamydomonads. We designate this group as the ‘Oophila’ clade, within which the symbiotic algae are further divided into four distinct subclades. Phylogenies of the host amphibians and their algal symbionts are only partially congruent, suggesting that host-switching and co-speciation both play roles in their associations. We also established conditions for isolating and rearing algal symbionts from amphibian egg capsules, which should facilitate further study of these egg mass specialist algae

Beyond ‘Rising Tides’ and ‘Lying Flat’: Emergent Cultural Practices Among Youth in Urban China

In their article, “Beyond ‘Rising Tides’ and ‘Lying Flat’: Emergent Cultural Practices Among Youth in Urban China”, Diego Gullotta and Lili Lin examine how Chinese youth are positioned within the dominant culture, how young people appropriate space in their emergent cultural practices, and how they negotiate meaning-making. The article first analyses the rising tides (houlang) video, sponsored jointly by the state and the private sector, and argues that it reduces youth to a homogenous subject inscribed into the discourse of “China’s rise” (zhongguo jueqi) via emotional mobilization. The “lying flat” phenomenon represents young people’s negative response to this mobilization, yet it still falls into the dichotomous discourse of “positive/negative energy”. Moving beyond this discourse, the article provides three cases of emergent cultural practices among urban middle-class youth to explore to what extent can these practices, characterized by knowledge and fluidity, exceed the logic of the state and the market

Multi-messenger Study of Galactic Diffuse Emission with LHAASO and IceCube Observations

With the breakthrough in PeV gamma-ray astronomy brought by the LHAASO experiment, the high-energy sky is getting richer than before. Lately, LHAASO Collaboration reported the observation of a gamma-ray diffuse emission with energy up to the PeV level from both the inner and outer Galactic plane. In these spectra, there is one bump that is hard to explain by the conventional cosmic-ray transport scenarios. Therefore, we introduce two extra components corresponding to unresolved sources with exponential-cutoff-power-law (ECPL) spectral shape, one with an index of 2.4, and 20 TeV cutoff energy, and another with index of 2.3 and 2 PeV cutoff energy. With our constructed model, we simulate the Galactic diffuse neutrino flux and find our results are in full agreement with the latest IceCube Galactic plane search. We estimate the Galactic neutrino contributes of $\sim 9\%$ of astrophysical neutrinos at 20 TeV. In the high-energy regime, as expected most of the neutrinos observed by IceCube should be from extragalactic environments.Comment: 10 pages, 8 figures, comments are welcome, accepted by PR

The Value of CT Enhancement Degree in Prognosis of Pancreatic Cancer

Objective: To explore the prognostic value of CT enhancement degree of pancreatic cancer in pancreatic cancer. Methods: From January 2019 to January 2022, 50 patients with pancreatic cancer who came to our hospital for pathological confirmation were selected. Prior to surgery, use multiphase CT of the pancreas to complete enhanced scans. After surgery, the patient's survival period, clinical treatment effectiveness, and imaging data are used as research variables. In the scanning diagnosis, it is necessary to collect the patient's age, gender, tumor location and size, differentiation process, CT value, etc. Create a mathematical model based on the collected data and complete the experimental research work. Results: Univariate analysis showed that the prognosis of pancreatic cancer patients with higher enhancement degree in each stage (P<0.05 in each stage) was better. Multivariate analysis showed that tumor differentiation (P=0.0118), TNM staging (P=0.004), and portal vein enhancement (P<0.001) can be independent predictors of patient prognosis. Conclusion: The lower the CT enhancement degree of pancreatic cancer, the worse the prognosis

A New Scenario of Solar Modulation Model during the Polarity Reversing

When the Galactic Cosmic Rays (GCRs) entering the heliosphere, they encounter the solar wind plasma, and their intensity is reduced, so-called solar modulation. The modulation is caused by the combination of a few factors, such as particle energies, solar activity and solar disturbance. In this work, a 2D numerical method is adopted to simulate the propagation of GCRs in the heliosphere with SOLARPROP, and to overcome the time-consuming issue, the machine learning technique is also applied. With the obtained proton local interstellar spectra (LIS) based on the observation from Voyager 1 and AMS-02, the solar modulation parameters during the solar maximum activity of cycle 24 have been found. It shows the normalization and index of the diffusion coefficient indeed reach a maximal value in February 2014. However, after taking into account the travel time of particles with different energies, the peak time was found postponed to November 2014 as expected. The nine-month late is so-called time lag.Comment: 10 pages, 8 figure