A network-based ranking system for American college football

American college football faces a conflict created by the desire to stage national championship games between the best teams of a season when there is no conventional playoff system to decide which those teams are. Instead, ranking of teams is based on their record of wins and losses during the season, but each team plays only a small fraction of eligible opponents, making the system underdetermined or contradictory or both. It is an interesting challenge to create a ranking system that at once is mathematically well-founded, gives results in general accord with received wisdom concerning the relative strengths of the teams, and is based upon intuitive principles, allowing it to be accepted readily by fans and experts alike. Here we introduce a one-parameter ranking method that satisfies all of these requirements and is based on a network representation of college football schedules.Comment: 15 pages, 3 figure

A novel, simple, and sensitive colorimetric method to determine aromatic amino acid aminotransferase activity using the Salkowski reagent

This study describes the development of a new colorimetric assay to determine aromatic amino acid aminotransferase (ArAT) activity. The assay is based on the transamination of l-tryptophan in the presence of 2-oxoglutarate, which yields indole-3-pyruvate (IPyA). The amount of IPyA formed was quantified by reaction with the Salkowski reagent. Optimized assay conditions are presented for ArAT isozymes isolated from Pseudomonas putida. For comparative purposes, ArAT activity was also determined by high-performance liquid chromatography. ArAT activity staining in polyacrylamide gels with the Salkowski reagent is also presented

Plant growth promotion properties of bacterial strains isolated from the rhizosphere of the Jerusalem artichoke ( Helianthus tuberosus

The Jerusalem artichoke (JA; Helianthus tuberosus), known to be tolerant to salt-alkaline soil conditions, has been cultivated for many years in the Yellow River delta, Shandong Province coastal zone, in China. The aim of our study was to isolate nitrogen-fixing bacteria colonizing the rhizosphere of JA and characterize other plant growth promotion properties. The ultimate goal was to identify isolates that could be used as inoculant benefiting an economic crop, in particular for improving wheat growth production in the Yellow River delta. Bacterial strains were isolated from the rhizosphere soil of the JA on the basis of growth on nitrogen-free Ashby medium. Identification and phylogenetic analysis was performed after nucleotide sequencing of 16S rRNA gene. Plant growth-promoting (PGP) traits such as nitrogen fixation activity, phosphate solubilization activity, indole-3-acetic acid (IAA) production was determined using conventional methods. Eleven strains were isolated and six of them were further examined for their level of salt tolerance and their effect on plant growth promotion. Inoculation of Enterobacter spp. strain N10, on JA and wheat, led to significant increase in both dry weight root and shoot height. Enterobacter spp. N10 appeared as the best PGP rhizobacteria to increase wheat productivity in future field applications.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Isolation and characterization of two plant growth-promoting bacteria from the rhizoplane of a legume (Lupinus albescens) in sandy soil

Duas linhagens bacterianas que apresentaram amplificação de parte do gene nifH, RP1p e RP2p, pertencentes aos gêneros Enterobacter e Serratia, foram isoladas do rizoplano de Lupinus albescens. Essas bactérias são Gram-negativas, com formato de bastonete, móveis, anaeróbias facultativas e apresentam multiplicação rápida, com colônias alcançando diâmetros de 3–4 mm em 24 h de incubação a 28 ºC. RP1p e RP2p também foram capazes de multiplicação em temperaturas elevadas, como 40 ºC, na presença de alta concentração de NaCl (2–3 % v/v) e em valores de pH que variaram de 4 a 10. A linhagem RP1p foi capaz de utilizar 10 das 14 fontes de carbono avaliadas, enquanto a linhagem RP2p utilizou nove. Os isolados produziram sideróforos e compostos indólicos, mas foram incapazes de solubilizar fosfatos. A inoculação de L. albescens com as linhagens RP1p e RP2p resultou em aumento significativo do peso das plantas secas, o que demonstra que essas bactérias apresentam propriedades que favorecem o crescimento vegetal.Two bacterial strains that amplified part of the nifH gene, RP1p and RP2p, belonging to the genus Enterobacter and Serratia, were isolated from the rhizoplane of Lupinus albescens. These bacteria are Gram-negative, rod-shaped, motile, facultative anaerobic, and fast-growing; the colonies reach diameters of 3–4 mm within 24 h of incubation at 28 °C. The bacteria were also able to grow at temperatures as high as 40 °C, in the presence of high (2–3 % w/v) NaCl concentrations and pH 4 -10. Strain RP1p was able to utilize 10 of 14 C sources, while RP2p utilized nine. The isolates produced siderophores and indolic compounds, but none of them was able to solubilize phosphate. Inoculation of L. albescens with RP1p and RP2p strains resulted in a significant increase in plant dry matter, indicating the plant-growth-promoting abilities of these bacteria

Functional abilities of cultivable plant growth promoting bacteria associated with wheat (Triticum aestivum L.) crops

Abstract In the pursuit of sustainable agriculture, bioinoculants usage as providers of a crop's needs is a method to limit environmental damage. In this study, a collection of cultivable putative plant growth promoting (PGP) bacteria associated with wheat crops was obtained and this bacterial sample was characterized in relation to the functional diversity of certain PGP features. The isolates were obtained through classical cultivation methods, identified by partial 16S rRNA gene sequencing and characterized for PGP traits of interest. Functional diversity characterization was performed using Categorical Principal Component Analysis (CatPCA) and Multiple Correspondence Analysis (MCA). The most abundant genera found among the 346 isolates were Pseudomonas, Burkholderia, and Enterobacter. Occurrence of PGP traits was affected by genus, niche, and sampling site. A large number of genera grouped together with the ability to produce indolic compounds; phosphate solubilization and siderophores production formed a second group related to fewer genera, in which the genus Burkholderia has a great importance. The results obtained may help future studies aiming prospection of putative plant growth promoting bacteria regarding the desired organism and PGP trait

Practical Application of Methanol-Mediated Mutualistic Symbiosis between Methylobacterium Species and a Roof Greening Moss, Racomitrium japonicum

Bryophytes, or mosses, are considered the most maintenance-free materials for roof greening. Racomitrium species are most often used due to their high tolerance to desiccation. Because they grow slowly, a technology for forcing their growth is desired. We succeeded in the efficient production of R. japonicum in liquid culture. The structure of the microbial community is crucial to stabilize the culture. A culture-independent technique revealed that the cultures contain methylotrophic bacteria. Using yeast cells that fluoresce in the presence of methanol, methanol emission from the moss was confirmed, suggesting that it is an important carbon and energy source for the bacteria. We isolated Methylobacterium species from the liquid culture and studied their characteristics. The isolates were able to strongly promote the growth of some mosses including R. japonicum and seed plants, but the plant-microbe combination was important, since growth promotion was not uniform across species. One of the isolates, strain 22A, was cultivated with R. japonicum in liquid culture and in a field experiment, resulting in strong growth promotion. Mutualistic symbiosis can thus be utilized for industrial moss production

A Naturally Associated Rhizobacterium of Arabidopsis thaliana Induces a Starvation-Like Transcriptional Response while Promoting Growth

Plant growth promotion by rhizobacteria is a known phenomenon but the underlying mechanisms are poorly understood. We searched for plant growth-promoting rhizobacteria that are naturally associated with Arabidopsis thaliana to investigate the molecular mechanisms that are involved in plant growth-promotion. We isolated a Pseudomonas bacterium (Pseudomonas sp. G62) from roots of field-grown Arabidopsis plants that has not been described previously and analyzed its effect on plant growth, gene expression and the level of sugars and amino acids in the host plant. Inoculation with Pseudomonas sp. G62 promoted plant growth under various growth conditions. Microarray analysis revealed rapid changes in transcript levels of genes annotated to energy-, sugar- and cell wall metabolism in plants 6 h after root inoculation with P. sp. G62. The expression of several of these genes remained stable over weeks, but appeared differentially regulated in roots and shoots. The global gene expression profile observed after inoculation with P. sp. G62 showed a striking resemblance with previously described carbohydrate starvation experiments, although plants were not depleted from soluble sugars, and even showed a slight increase of the sucrose level in roots 5 weeks after inoculation. We suggest that the starvation-like transcriptional phenotype - while steady state sucrose levels are not reduced - is induced by a yet unknown signal from the bacterium that simulates sugar starvation. We discuss the potential effects of the sugar starvation signal on plant growth promotion

The relationship between doses of mindfulness-based programs and depression, anxiety, stress, and mindfulness: a dose-response meta-regression of randomized controlled trials

Abstract Objectives: Research with mindfulness-based programs (MBPs) has found participating in an MBP to predict beneficial outcomes, however, there is currently mixed research regarding the most helpful dose. This review aimed to determine whether different doses related to MBPs significantly predict outcomes. Methods: Systematic literature searches of electronic databases and trial registration sites for all randomized controlled trials of MBPs identified 203 studies (N=15,971). Depression was the primary outcome at post-program and follow-up, with secondary outcomes being mindfulness, anxiety and stress. Doses examined related to session numbers, duration and length, facilitator contact and practice. Dose-response relationships were analyzed using meta-regression in R with separate analyses for inactive and active controls. Results: Initial meta-analyses found significant between-group differences favoring MBPs for all outcomes. Meta-regression results suggested significant dose-response relationships for the mindfulness outcome for doses relating to face-to-face contact (d=0.211; C.I.[0.064,0.358]), program intensity (d=0.895; C.I.[0.315,1.474]) and actual program use (d=0.013; C.I.[0.001,0.024]). The majority of results for psychological outcomes, including depression, were not significant. Conclusions: This meta-regression examines dose-response relationships for different types and doses relating to MBPs. Considered together, MBPs appeared helpful compared to controls, supporting previous research. Based on meta-regression results, there was no evidence that larger doses are more helpful than smaller doses for predicting psychological outcomes; a finding consistent with some previous research particularly with non-clinical populations. Additionally, greater contact, intensity and actual use of MBPs predicting increased mindfulness corresponds with previous research and theory. Potential limitations and recommendations for future research are explored