The Schulz-Flory distribution is a mathematical function that describes the relative ratios of polymers of different length after a polymerization process, based on their relative probabilities of occurrence. Carbon nanotubes (CNTs) are big carbon molecules which have a very high length-to-diameter ratio, somewhat similar to polymer molecules. Large amounts of ultralong CNTs have not been obtained although they are highly desired. Here, we report that the Schulz-Flory distribution can be applied to describe the relative ratios of CNTs of different lengths produced with a floating chemical vapor deposition process, based on catalyst activity/deactivation probability. With the optimized processing parameters, we successfully synthesized 550-mm-long CNTs, for which the catalyst deactivation probability of a single growth step was ultralow. Our finding bridges the Schulz-Flory distribution and the synthesis of one-dimensional nanomaterials for the first time, and sheds new light on the rational design of process toward controlled production of nanotubes/nanowires.
The poor health status of the Western honey bee, Apis mellifera, compared to its Eastern counterpart, Apis cerana, is remarkable. This has been attributed to lower pathogen prevalence in A. cerana colonies and to their ability to survive infestations with the ectoparasitic mite, Varroa destructor. These properties have been linked to an enhanced removal of dead or unhealthy immature bees by adult workers in this species. Although such hygienic behavior is known to contribute to honey bee colony health, comparative data of A. mellifera and A. cerana in performing this task are scarce. Here, we compare for the first time the removal of freeze-killed brood in one population of each species and over two seasons in China. Our results show that A. cerana was significantly faster than A. mellifera at both opening cell caps and removing freeze-killed brood. The fast detection and removal of diseased brood is likely to limit the proliferation of pathogenic agents. Given our results can be generalized to the species level, a rapid hygienic response could contribute to the better health of A. cerana. Promoting the fast detection and removal of worker brood through adapted breeding programs could further improve the social immunity of A. mellifera colonies and contribute to a better health status of the Western honey bee worldwide.
Abstract. We determine regularity results for energy minimizing maps from an n-dimensional Riemannian polyhedral complex X into a CAT(1) space. Provided that the metric on X is Lipschitz regular, we prove Hölder regularity with Hölder constant and exponent dependent on the total energy of the map and the metric on the domain. Moreover, at points away from the (n − 2)-skeleton, we improve the regularity to locally Lipschitz. Finally, for points x ∈ X (k) with k ≤ n − 2, we demonstrate that the Hölder exponent depends on geometric and combinatorial data of the link of x ∈ X.
BACKGROUND: Diet plays an important role in shaping the composition of gut microbiota. Starch is the main source of carbohydrates in diets of broilers. This study investigated the effects of dietary corn starch and resistant starch on composition and function of caecal microbiota of broilers. A total of 320, 1-day-old male Arbor Acres broiler chicks were randomly assigned into five groups including normal corn-soybean (NC) diet, corn starch (CS) diet group, 4%, 8% and 12% resistant starch (RS) diet groups. The caecal contents of 42-day old broilers were sampled and microbiota community was analysed with 16S rRNA gene sequences.
RESULTS: The CS group increased the abundances of Bilophila, Eggerthella, Olsenella and Sellimonas and decreased proportion of Akkermansia, Eisenbergiella, Oscillospira, Ruminococcaceae NK4A214 group and Synergistes in the caecum of birds compared to the NC group. However, the birds from RS groups had higher abundances of Anaerofilum, Bacteroides, Desulfovibrio andParasutterella and lower abundances of Alistipes, Bilophila, Christensenellaceae R-7 group, Eggerthella and Ruminiclostridium 1 than the CS group. Functional prediction of these changes in microbiota revealed that the CS diet drove caecal microbiota that were more inclined to utilize carbohydrates through glycolysis/gluconeogenesis metabolism, while the 8%RS and 12%RS diets depleted microbial glycolysis/gluconeogenesis and amino acids metabolism. CONCLUSION: Dietary CS and RS alter the microbial composition and diversity, and modulate the metabolic pathways of microbial metabolism in caecum of broilers, which may further affect nutrient utilization and hindgut health of the host.
Traditionally, statistical methods for futility analysis are developed based on a single study. To establish a drug's effectiveness, usually at least two adequate and well-controlled studies need to demonstrate convincing evidence on its own. Therefore, in a standard clinical development program in chronic diseases, two independent studies are generally conducted for drug registration. This paper proposes a statistical method to combine interim data from two independent and similar studies for interim futility analysis and shows that the conditional power approach based on combined interim data has better operating characteristics compared to the approach based on single-trial interim data, even with small to moderate heterogeneity on the treatment effects between the two studies.
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