Predictive performance modelling of parallel component compositions

Large-scale scientific computing applications frequently make use of closely-coupled distributed parallel components. The performance of such applications is therefore dependent on the component parts and their interaction at run-time. This paper describes a methodology for predictive performance modelling and evaluation of parallel applications composed of multiple interacting components. In this paper, the fundamental steps and required operations involved in the modelling and evaluation process are identified—including component decomposition, component model combination, M×N communication modelling, dataflow analysis and overall performance evaluation. A case study is presented to illustrate the modelling process and the methodology is verified through experimental analysis.

A molecular phylogeny of <Emphasis Type="Italic">Dorylus</Emphasis> army ants provides evidence for multiple evolutionary transitions in foraging niche

Background  

Army ants are the prime arthropod predators in tropical forests, with huge colonies and an evolutionary derived nomadic life style. Five of the six recognized subgenera of Old World Dorylus army ants forage in the soil, whereas some species of the sixth subgenus (Anomma) forage in the leaf-litter and some as conspicuous swarm raiders on the forest floor and in the lower vegetation (the infamous driver ants). Here we use a combination of nuclear and mitochondrial DNA sequences to reconstruct the phylogeny of the Dorylus s.l. army ants and to infer the evolutionary transitions in foraging niche and associated morphological adaptations.     

Social common mole-rats enhance outbreeding via extra-pair mating

Females in many species engage in matings with males that are not their social mates. These matings are predicted to increase offspring heterozygosity and fitness, and thereby prevent the deleterious effects of inbreeding. We tested this hypothesis in a cooperative breeding mammal, the common mole-rat Cryptomys hottentotus hottentotus. Laboratory-based studies suggested a system of strict social monogamy, while recent molecular studies indicate extensive extra-pair paternity despite colonies being founded by an outbred pair. Our data show that extra-pair and within-colony breeding males differed significantly in relatedness to breeding females, suggesting that females may gain genetic benefits from breeding with non-resident males. Extra-colony male mating success was not based on heterozygosity criteria at microsatellite loci; however, litters sired by extra-colony males exhibited increased heterozygosity. While we do not have the data that refute a relationship between individual levels of inbreeding (Hs) and fitness, we propose that a combination of both male and female factors most likely explain the adaptive significance of extra-pair mating whereby common mole-rats maximize offspring fitness by detecting genetic compatibility with extra-pair mates at other key loci, but it is not known which sex controls these matings.     

MAP4K4 Inhibition Promotes Survival of Human Stem Cell-Derived Cardiomyocytes and Reduces Infarct Size In Vivo

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Stimulation of conversion rates and bacterial activity in a silage-fed two-phase biogas process by initiating liquid recirculation

The effects of liquid recirculation on a liquefaction-acidogenic reactor in an anaerobic two-phase digesting system operating with grass-clover silage was studied during 40 days after initiating recirculation of effluent from the methanogenic reactor to the liquefaction-acidogenic reactor. An increase in alkalinity and, thus, an increase in pH from 5.2 to 6.0 occurred in the liquefaction-acidogenic reactor. During the same period, a 10-fold increase (from 0.2 to 1.9 g·l^–1·h^–1) in the degradation rate of mannitol and an almost 9-fold increase in the activity of hydrogenotrophic methanogens was observed. The estimated number of these bacteria increased by one order of magnitude. The average degradation rate of lactate increased 3-fold, probably as a consequence of the more efficient hydrogen consumption by the hydrogenotrophic methanogens. An observed increase in net mineralization of organic nitrogen compounds was probably the main reason for an enhanced net production of organic acids (from 0.2 to 0.9 g·l^–1·d^–1). The liquefaction of cellulose and hemicellulose was low from the start of recirculation (3% and 20% reduction, respectively) and did not seem to be affected by the liquid recirculation. This was in accordance with the low number of cellulose degraders (4.0·10² counts·ml^–1) observed. The results from this investigation show that the initiation of liquid recirculation in silage-fed two-phase biogas processes will stimulate the activity of hydrogenotrophic methanogens in the liquefaction-acidogenic reactor. This will lead to more thermodynamically favourable conditions for acidification reactions which are dependent upon interspecies transfer of reducing equivalents.Abbreviations COD chemical oxygen demand - CSTR completely stirred tank reactor - HRT hydraulic retention time - LA-reactor liquefaction-acidogenic reactor - M-reactor methanogenic reactor - MPN most probable number - OLR organic loading rate - SMA specific methanogenic activity - SRT solids retention time - TKN total Kjeldahl nitrogen - ts total solids - tss total suspended solids - vs volatile solids - vss volatile suspended solids     

Replication of long-bone length QTL in the F9-F10 LG,SM advanced intercross

Quantitative trait locus (QTL) mapping techniques are frequently used to identify genomic regions associated with variation in phenotypes of interest. However, the F₂ intercross and congenic strain populations usually employed have limited genetic resolution resulting in relatively large confidence intervals that greatly inhibit functional confirmation of statistical results. Here we use the increased resolution of the combined F₉ and F₁₀ generations (n = 1455) of the LG,SM advanced intercross to fine-map previously identified QTL associated with the lengths of the humerus, ulna, femur, and tibia. We detected 81 QTL affecting long-bone lengths. Of these, 49 were previously identified in the combined F₂-F₃ population of this intercross, while 32 represent novel contributors to trait variance. Pleiotropy analysis suggests that most QTL affect three to four long bones or serially homologous limb segments. We also identified 72 epistatic interactions involving 38 QTL and 88 novel regions. This analysis shows that using later generations of an advanced intercross greatly facilitates fine-mapping of confidence intervals, resolving three F₂-F₃ QTL into multiple linked loci and narrowing confidence intervals of other loci, as well as allowing identification of additional QTL. Further characterization of the biological bases of these QTL will help provide a better understanding of the genetics of small variations in long-bone length. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.