The ancestral recombination graph (ARG) contains the full genealogical information of the sample, and many population genetic inference problems can be solved using inferred or sampled ARGs. In particular, the waiting distance between tree changes along the genome can be used to make inference about the distribution and evolution of recombination rates. To this end, we here derive an analytic expression for the distribution of waiting distances between tree changes under the sequentially Markovian coalescent model and obtain an accurate approximation to the distribution of waiting distances for topology changes. We use these results to show that some of the recently proposed methods for inferring sequences of trees along the genome provide strongly biased distributions of waiting distances. In addition, we provide a correction to an undercounting problem facing all available ARG inference methods, thereby facilitating the use of ARG inference methods to estimate temporal changes in the recombination rate.

A variety of ceramics and polymers exists that can be used as bone substitute materials with desirable properties such as biocompatibility and osteoconductivity. A key feature missing in these bone substitutes, or scaffolds, is the ability to bear loads. This work explored two methods for solving this problem. The first used cancellous bone taken from bovine femoral bone to create a natural scaffold through a heat treating process that eliminated the organic components and sintered the bone minerals, known as hydroxyapatite, together. The strength and Young's modulus of the natural scaffold were greatly improved after polymer infiltration with polymethylmethacrylate. Unfortunately, compression testing revealed that there was not a good interfacial bond between the mineral and polymer phases. The second method employed a freeze-casting technique to create synthetic hydroxyapatite scaffolds that have an aligned lamellar microstructure. By varying the amount of hydroxyapatite in the initial slurry mixture and the cooling rate, synthetic scaffolds with a range of porosities and strengths was produced. The highest solid loading and fastest cooling rate produced a scaffold with a strength and modulus approaching that of cortical bone. Further study is required to produce a two phase composite that is chemically bonded together for optimal performance. The synthetic scaffolds, with their tunable mechanical properties and ease of fabrication, make them a promising material for a load-bearing bone substitute

The authors developed and validated the Korean version of the Experiences in Close Relationships-Short Form (K-ECRR-SF) with the goal of developing a culturally responsive scale. In study 1, a Rasch analysis was conducted on the 36 original items in the ECR-Revised (ECR-R) to select items that best represent anxiety and avoidance subscales by considering cultural equivalence. In study 2, confirmatory factor analysis (CFA) was conducted for the selected 12 items with a different sample. The factor structures of the ECR-R and K-ECRR-SF through CFA were then compared through CFA. In addition, the K-ECRR-SF items were tested for related constructs (i.e., reassurance and support seeking, loneliness, dyadic satisfaction, depression, anxiety, and fear of intimacy) to its criterion evidence. The newly developed K-ECRR-SF is confirmed to be valid and culturally responsive scale in measuring attachment in Korea.

Lithium-air batteries show a great promise in electrochemical energy storage with their theoretical specific energy comparable to gasoline. Discharge products such as Li 2O 2 or Li 2CO 3 are insoluble in several major nonaqueous electrolytes, and consequently precipitate at the reaction sites. These materials are also low in electric conductivity. As a result, the reduced pore space and electrode passiviation increase the reaction resistance and consequently reduce discharge voltage and capability. This work presents a modeling study of discharge product precipitation and effects for lithium-air batteries. Theoretical analysis is also performed to evaluate the variations of important quantities including temperature, species concentrations, and electric potentials. Precipitation growth modes on planar, cylindrical and spherical surfaces are discussed. A new approach, following the study of ice formation in PEM fuel cells, is proposed. Validation is carried out against experimental data in terms of discharge voltage loss. © 2012 Elsevier Ltd. All rights reserved.

Objective: This study was designed to examine the effects of sugar substitutes on the gut microbiome.

Methods: PUBMED was used to find articles that studied the gut microbiome after consumption of a sugar substitute in humans. Both observational and interventional studies were selected for this review.

Results: Starting with 31 articles found on PUBMED, 5 articles were included to be reviewed after 26 articles were excluded. Three natural sugar substitutes and four categories of artificial sweeteners were studied. Maltitol, lactitol, and isomalt were the natural sugar substitutes, and aspartame, acesulfame-K, non-caloric artificial sweeteners, and saccharin were the artificial sweeteners. The outcomes for Bifidobacteria, Bacteroides, Clostridium, Lactobacilli, Fusobacterium prausnitzii, and Enterobacteriaceae were addressed. Natural sugar substitutes were seen to increase bacterial populations that are believed to be beneficial to humans while artificial sweeteners established bacterial populations that are considered harmful to health.

Conclusions: The studies examined suggest cautious use of artificial sweeteners due to its effects on the gut microbiome while natural sugar substitutes could have potential health benefits

한국적 다문화주의의 전개와 특성: 국가와 시민사회의 역할을 중심으로 Hanguk sahoehak, vol. 42, no. 2 (2008).