Interpretation of AMS-02 beryllium isotope fluxes using data-driven production cross sections

The Be isotopic measurements preliminarily reported by the AMS-02 Collaboration have reached an unprecedented energy of 12 GeV/$n$. As secondary cosmic rays (CRs), the Be isotopes include both stable and unstable species, which are crucial for constraining the propagation parameters of Galactic CRs. However, uncertainties in their production cross sections can skew the interpretation of the CR data, especially when cross-section measurements are of significantly lower quality than CR measurements. In this work, we consider the uncertainties of the cross sections to interpret the Be isotopic data by adopting a cross-section parametrization that fully utilizes the available experimental data. Owing to the high-quality measurements of the $^7$Be production cross section, we innovatively employ $^7$Be instead of $^9$Be to constrain propagation parameters. Notably, the diffusion halo thickness is constrained to $5.67\pm0.76$~kpc, representing a moderate value compared to previous analogous works. Combining the well-constrained CR propagation model and the precise CR measurements of $^9$Be, we conversely constrain the major production cross section of $^9$Be and find that it ought to be remarkably lower than previously thought. Our analysis also questions the reliability of certain cross sections measured by some experiments, potentially marking the first time CR data has been used to identify dubious nucleon production cross sections. The method presented in this work holds promise for analyzing upcoming isotopic data from other nuclei.Comment: 15 pages, 9 figure

Reexamine the dark matter scenario accounting for the positron excess in a new cosmic ray propagation model

The positron excess in cosmic rays has stimulated a lot of interests in the last decade. The dark matter origin of the extra positrons has attracted great attention. However, the $\gamma$-ray search set very stringent constraints on the dark matter annihilation/decay rate, which leads to great disfavor of the dark matter scenario. In the work, we incorporate the recent progress in cosmic rays propagation and reexamine the dark matter scenario accounting for the positron excess. Recent observations indicate that cosmic rays propagation in the Milky Way may be not uniform and diffusion in the Galactic disk should be slower than that in the halo. In the spatial-dependent propagation model, the positrons/electrons are more concentrated in the disk and lead to smaller dark matter annihilation/decay rate to account for the positron excess and also a smaller deficit in the background positron flux. Especially for the $\mu^+\mu^-$ channel the positron spectrum fit the AMS-02 latest data perfectly and the annihilation rate satisfies all the present constraints from $\gamma$-ray and CMB observations.Comment: 11 pages, 4 figure

Colloid chemistry approach to understand the storage stability of fermented carrot juice

Probiotic-fermented carrot juice (PFCJ) is a functional food, for which colloidal stability during storage is essential. The water-soluble polysaccharides (WSPs) it contains provide this stability as colloidal stabilizers; they are pectinic, mainly containing galacturonic acid, galactose and arabinose as monosaccharide units. The particle-size distribution, ζ potential, centrifugal sediment ratio, soluble solids content, total acid and structural features of these WSPs were evaluated as functions of storage time. The PFCJ displayed pseudoplastic fluid behavior. Molecular weight and solid morphology of WSPs did not change significantly with storage, although the molecular weights of WSPs showed a slight decrease. The storage stability is ascribed to its WSPs acting as electrosteric stabilizers (which are very robust colloidal stabilizers) by adsorbing onto the insoluble plant cell wall polysaccharides which comprise the dispersed phase in the suspension. Viscosity and particle size remained relatively stable when stored at 4 °C and 25 °C, while centrifugal sediment ratio, soluble solids content and total acid all increased significantly; these can also be explained in terms of the structure of the WSPs. This can provide guidance to choosing ingredients which improve storage stability and other properties of importance to consumers by using the precepts of electrosteric colloidal stabilization: e.g. the presence of water-soluble polysaccharides with long hydrophilic moieties

Experimental realization of universal high-dimensional quantum gates with ultra-high fidelity and efficiency

Qudit, a high-dimensional quantum system, provides a larger Hilbert space to process the quantum information and has shown remarkable advantages over the qubit counterparts. It is a great challenge to realize the high fidelity universal quantum gates with qudits. Here we theoretically propose and experimentally demonstrate a set of universal quantum gates for a single optical qudit with four dimensions (including the generalized Pauli $X_4$ gate, Pauli $Z_4$ gate, and all of their integer powers), which are encoded in the polarization-spatial degree of freedom without multiple unstable cascaded interferometers. Furthermore, we also realize the controlled-$X_4$ gate and all of its integer powers. We have achieved both the ultra-high average gate fidelity $99.73\%$ and efficiency $99.47\%$, which are above the the error threshold for fault-tolerant quantum computation. Our work paves a way for the large-scale high-dimensional fault-tolerant quantum computation with a polynomial resource cost

Leakage Characteristic of Helical Groove Seal Designed in Reactor Coolant Pump

Helical groove seal is designed in reactor coolant pump to control the leakage along the front surface of the impeller face due to its higher resistance than the circumferentially grooved seal. The flow and the friction factors in helical groove seals are predicted by employing a commercial CFD code, FLUENT. The friction factors of the helical groove seals with helix angles varying from 20 deg to 50 deg, at a range of rotational speed and axial Reynolds number, were, respectively, calculated. For the helically grooved stator with the helix angle greater than 20 deg, the leakage shows an upward trend with the helix angle. The circumferentially grooved stator has a lower resistance to leakage than the 20 deg and 30 deg stators. It can be predicated that, for a bigger helix angle, the friction factor increases slightly with an increase in high axial Reynolds number, which arises from the high-pressure operation condition, and the friction factor is generally sensitive to changes in the helix angle in this operation condition. The study lays the theoretical foundation for liquid seal design of reactor coolant pump and future experimental study to account for the high-pressure condition affecting the leakage characteristic

Alterations in microRNA expression profiles in inflamed and non-inflamed ascending colon mucosae of patients with active Crohn's disease

Background and aims The miRNA expression profiles of the terminal ileum, sigmoid colon, and rectal mucosa of adult patients with active Crohn';s disease (CD) have been previously reported. The purpose of this study was to identify dysregulated miRNAs in the mucosa of the ascending colon. Methods Biopsy tissue samples were taken from the mucosae of inflammatory (iCD) or non-inflammatory (niCD) areas of the ascending colons of adult patients with active CD. miRNA and mRNA expression profiles were detected using microarray analyses. miRNAs and mRNAs demonstrating significant differences were validated via quantitative real-time PCR (qRT-PCR). Luciferase reporter genes were used to measure two miRNAs inhibition of potential target genes in human 293T cells in vitro. Results Compared with the HC group, the ascending colon miRNA expression profiles revealed that 43 miRNAs were significantly up-regulated and 35 were down-regulated in the iCD group. The mRNA expression profiles indicated that 3,370 transcripts were significantly differentially expressed in the ascending colon, with 2169 up-regulated and 1201 down-regulated mRNAs in the iCD group, and only 20 miRNAs demonstrated significant differential expression in the niCD group. In contrast, nearly 100 miRNAs significantly varied between the iCD and niCD groups. Finally, luciferase reporter gene assays showed that hsa-miR-16-1 directly regulated the human C10orf54 gene and that they were negatively correlated. Conclusions Our results indicated that the differentially expressed miRNAs and mRNAs were related to immune inflammation and intestinal flora. The data provide preliminary evidence that the occurrence of CD involves the inhibition of C10orf54 expression by hsa-miR-16-1