Evolution and networks in ancient and widespread symbioses between Mucoromycotina and liverworts

Like the majority of land plants, liverworts regularly form intimate symbioses with arbuscular mycorrhizal fungi (Glomeromycotina). Recent phylogenetic and physiological studies report that they also form intimate symbioses with Mucoromycotina fungi and that some of these, like those involving Glomeromycotina, represent nutritional mutualisms. To compare these symbioses, we carried out a global analysis of Mucoromycotina fungi in liverworts and other plants using species delimitation, ancestral reconstruction, and network analyses. We found that Mucoromycotina are more common and diverse symbionts of liverworts than previously thought, globally distributed, ancestral, and often co-occur with Glomeromycotina within plants. However, our results also suggest that the associations formed by Mucoromycotina fungi are fundamentally different because, unlike Glomeromycotina, they may have evolved multiple times and their symbiotic networks are un-nested (i.e., not forming nested subsets of species). We infer that the global Mucoromycotina symbiosis is evolutionarily and ecologically distinctive

Importance of traveler attitudes in the choice of public transportation to work: findings from the Regional Transportation Authority Attitudinal Survey

Mode choice, Public transportation, Attitudes and perceptions, Factor analysis, Logistic regression, Elasticities,

A Spatial-Economic Multimodal Transportation Simulation Model For US Coastal Container Ports

Assessing the potential demand for container ports and related multimodal transportation is critical for several purposes, including financial feasibility analysis and the evaluation of net economic benefits and their distribution. When developed in conjunction with a geographical information system, port-related demand analysis also provides needed input for assessment of selected environmental issues, such as truck traffic on local roads and related potential external costs, such as air pollution and noise. However, container port demand analysis is very difficult due to the complexities of international trade in containerised goods, inter-port competition, and potential strategic behaviour by several parties. Difficulties also arise from the many factors to be considered, major data requirements, and the computationally intensive nature of the problem. This paper summarises the development and application of a spatial-economic, multimodal container transportation demand simulation model for major US container ports. The underlying economic framework assumes shippers minimise the total general cost of moving containers from sources to markets. The model is validated and then used to estimate (1) annual container transportation service demand for major container ports, (2) the market areas served by selected ports, and (3) the impact on port demand and interport competition due to hypothetical changes in port use fees at selected ports. This paper first describes the model and the underlying economic reasoning, followed by the assumptions, computational algorithms, and the software architecture. Then, the trade data, transportation networks, and economic variables are described. After that, model simulation results are presented with qualifications, needed refinements, and future directions. Maritime Economics & Logistics (2003) 5, 158–178. doi:10.1057/palgrave.mel.9100067

Human intellectual disability genes form conserved functional modules in Drosophila

Contains fulltext : 124936.pdf (publisher's version ) (Open Access)Intellectual Disability (ID) disorders, defined by an IQ below 70, are genetically and phenotypically highly heterogeneous. Identification of common molecular pathways underlying these disorders is crucial for understanding the molecular basis of cognition and for the development of therapeutic intervention strategies. To systematically establish their functional connectivity, we used transgenic RNAi to target 270 ID gene orthologs in the Drosophila eye. Assessment of neuronal function in behavioral and electrophysiological assays and multiparametric morphological analysis identified phenotypes associated with knockdown of 180 ID gene orthologs. Most of these genotype-phenotype associations were novel. For example, we uncovered 16 genes that are required for basal neurotransmission and have not previously been implicated in this process in any system or organism. ID gene orthologs with morphological eye phenotypes, in contrast to genes without phenotypes, are relatively highly expressed in the human nervous system and are enriched for neuronal functions, suggesting that eye phenotyping can distinguish different classes of ID genes. Indeed, grouping genes by Drosophila phenotype uncovered 26 connected functional modules. Novel links between ID genes successfully predicted that MYCN, PIGV and UPF3B regulate synapse development. Drosophila phenotype groups show, in addition to ID, significant phenotypic similarity also in humans, indicating that functional modules are conserved. The combined data indicate that ID disorders, despite their extreme genetic diversity, are caused by disruption of a limited number of highly connected functional modules