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High throughput sequencing of gut microbiota helps to understand the nutrition and health of the host. In this sense, it is an important tool for improving wildlife conservation and management. Little is known about the microbial communities occupying the gastrointestinal tract and the differences of microbiota among primate species. We conducted a microbiome study of the gastrointestinal tract in golden snub-nosed monkey (Rhinopithecus roxellanae), green monkey (Chlorocebus aethiops sabaeus), and ring-tailed lemur (Lemur catta), using the 16S rRNA gene amplicon sequencing and shotgun metagenomic sequencing. The gastrointestinal tract of all three primates were characterized by Firmicutes, Bacteroidetes, and Proteobacteria, although the relative abundance of these taxa differed across non-human primate species and gastrointestinal segments. In addition, the stomach of the golden monkey demonstrated a strong signal of microbial metabolic activity, especially in metabolizing carbohydrate. Prevotella multisaccharivorax and Selenomonas bovis were the main contributors to the function, and the enzymes involved in these metabolic activities were mainly derived from the glycoside hydrolase (GH) family. Microbial composition and function vary widely across non-human primate species and gastrointestinal segments. Therefore, while faecal samples are necessary for studying many mammals, particularly in the wild, data from the gastrointestinal tract have the potential to greatly improve our knowledge of host-gut microbe interactions. This information can contribute to the development of conservation interventions and animal care protocols in the wild and captivity to more fully describe a species’ nutritional needs and advance health and survival.

Powder samples of La0.95T0.05CrxMn1−xO3 (T = Ca or Sr, 0.00 ≤ x ≤ 0.30), two series of ABO3 perovskite manganites, were synthesized using the sol–gel method. X-ray diffraction analysis showed that all the samples had a single ABO3 perovskite phase with space group R 3 ‾ c . Unique magnetic properties were obtained for the oxides: (i) the Curie temperature of each series of samples first increased and then decreased with increasing Cr content (x); (ii) the average molecular magnetic moment reached the maximum value when x = 0.08 for the Ca-doped samples, but it monotonically decreased with increasing x for the Sr-doped samples. This behavior was explained using an O 2p itinerant-electron model for magnetic oxides.

X-ray photoelectron spectra of the O 1s electrons of MnFe2O4, ZnFe2O4, ZnO, and CaO were used to estimate the average valence, ValO, of the oxygen anions in these samples. The absolute values of ValO for these samples were found to be distinctly lower than the traditional value of 2.0, suggesting that the total average valences of the cations are also lower than the conventionally accepted values owing to valence balance in the compounds. In addition, we analyzed the valence band spectra of the samples and investigated the distribution characteristics of the valence electrons. Keywords: Spinel ferrite, X-ray photoelectron spectra, Valence electron, Average valence, Ionization energy

The dependence of the magnetic moment of the perovskite manganites La1−xSrxMnO3 on the Sr doping level, x, is fitted using an oxygen 2p itinerant electron model for magnetic oxides (i.e., the IEO model), which is similar to the O 2p hole model proposed by Alexandrov et al. (Phys. Rev. Lett., 96 (2006) 117003). According to this IEO model, the itinerant electrons in these manganites are oxygen 2p electrons (or 2p holes) rather than 3d electrons, as assumed in the double-exchange interaction model. Furthermore, the proposed IEO model describes the process by which the itinerant electrons transit along the O2−–Mn2+–O2−–Mn3+–O1− ion chains in La1−xSrxMnO3 (x < 0.15), wherein a 2p hole is present in the outer orbit of the O1− anion and the magnetic moment of the Mn3+ cation is opposite to that of the Mn2+ cation.

The trends of the conduction band minima with the alloy compositions for the pseudomorphic Si 1−x−y Ge x C y alloys grown on (110) Si and Ge substrates are investigated theoretically with the use of the ab initio pseudopotential method and the virtual-crystal approximation. It is found that the minimum energy gaps are all indirect and not monotonically dependent on the compositions in some cases. In the case of the tensile and compressive strains, the minimum energy gap decreases and increases, respectively, as the C fraction increases and the Ge fraction is constant. Our result is in good agreement with other theoretical results for the Si 1−x Ge x system.