Could the 21-cm absorption be explained by the dark matter suggested by 8^8Be transitions?

The stronger than expected 21-cm absorption was observed by EDGES recently, and another anomaly of $^8$Be transitions would be signatures of new interactions. These two issues may be related to each other, e.g., pseudoscalar $A$ mediated fermionic millicharged dark matter (DM), and the 21-cm absorption could be induced by photon mediated scattering between MeV millicharged DM and hydrogen. This will be explored in this paper. For fermionic millicharged DM $\bar{\chi} \chi$ with masses in a range of $2 m_A < 2 m_{\chi} < 3 m_A$, the p-wave annihilation $\bar{\chi} \chi \to A A$ would be dominant during DM freeze-out. The s-wave annihilation $\bar{\chi} \chi$ $\to A, \gamma$ $\to e^+ e^-$ is tolerant by constraints from CMB and the 21-cm absorption. The millicharged DM can evade constraints from direct detection experiments. The process of $K^+ \to \pi^+ \pi^0$ with the invisible decay $\pi^0 \to \bar{\chi} \chi$ could be employed to search for the millicharged DM, and future high intensity $K^+$ sources, such as NA62, will do the job.Comment: 6 pages, 2 figures, the accepted version, EPJ

Effect of terrains on the volatiles of Cabernet Sauvignon wines grown in Loess Plateau region of China

Volatile compounds of young Cabernet Sauvignon wines from the flat and slope lands grown in Loess Plateau region (China) were investigated in this research. Among the volatile compounds analyzed by headspace solid phase microextraction (HS-SPME) with gas chromatography-mass spectrometry (GC-MS), a total of 43 and 45 volatile compounds were identified and quantified in the flat and slope lands wines, respectively. In the volatiles detected, higher alcohols formed the most abundant group in the aroma components of two wines, followed by esters and fatty acids. According to their odor active values (OAVs) and relative odor contribution (ROC), the aromatic profiles for two wines were similar, showing only quantitative but not qualitative differences. Ethyl octanoate, ethyl hexanoate and isoamyl acetate were found to jointly contribute to 98.8 and 99.2% of the global aroma of the flat and slope wines, respectively. These odorants are associated with “fruity’’ and ‘‘ripe fruit’’ odor descriptors. Wine from flat land with higher OAVs of ethyl octanoate and isoamyl acetate seems to have more intense fruity aromas (pineapple, pear and banana), with floral notes.Keywords: Cabernet Sauvignon wines, volatiles, terrains, Loess Plateau region, headspace solid phase microextraction (HS-SPME), gas chromatography-mass spectrometry (GC-MS

1-Amino­pyridinium triiodidoplumbate(II)

The title complex, (C5H7N2)[PbI3], consists of a 1-amino­pyridinium cation, disordered about a mirror plane, and a [PbI3]− anion. The Pb2+ ion (site symmetry ) is surrounded by six I atoms in a slightly distorted octa­hedral coordination. The PbI6 octa­hedra share faces, building up ∞ 1[PbI6/2] chains running along [010]. The cations are situated between the chains. Coulombic attractions and van der Waals inter­actions between the inorganic and organic components are mainly responsible for the cohesion of the structure

Noise in Genotype Selection Model

We study the steady state properties of a genotype selection model in presence of correlated Gaussian white noise. The effect of the noise on the genotype selection model is discussed. It is found that correlated noise can break the balance of gene selection and induce the phase transition which can makes us select one type gene haploid from a gene group.Comment: 8 pages, 4 figure

Anthropometric Characteristics of Chinese Professional Female Marathoners and Predicted Variables for their Personal Bests

To investigate anthropometric characteristic of Chinese professional female marathoners and suitable predicted variables correlated with their personal bests(PBs). During the process of talent identification for London Olympic game, 96 Chinese female long-distance runners were divided into international(<2 h 34 min), national(2 h 34min~2 h 45min) and average(2 h 45 min~3 h 19 min) levels according to their PBs in marathon. Selected anthropometric variables, including height, body mass, %body fat, girths, breadths, lengths and skin-fold thicknesses were measured. Only iliac crest skin-fold of international athletes were significantly lower than its in national group. Girth of forearm and lower limbs, length of lower limbs, and all skin-fold thicknesses of national athletes were significantly lower than those from average level group. % body fat, girth of forearm and calf, length of lower limbs, and skin-folds at sites of subscapular, abdominal and iliac crest of athletes from average level group were significantly higher than those in international athletes. Positive correlation was found between forearm girth and PBs, and between the subscapular, abdominal, iliac crest and triceps surae skin-folds and PB for total athletes. Negative correlation between biiliac breadth and PB in international athletes, and positive correlations between abdominal and triceps surae skin-folds and PBs in national athletes were found. For average runners, high positive correlation was found between upper arm girth and PBs, and between subscapular, abdominal, iliac crest and triceps surae skin-folds and PBs. The findings suggested that compared to stride length, stride frequency and efficiency were more important factors influencing running performance, which were in accordance with running technique in Chinese female marathoners