Self-trapping transition for nonlinear impurities embedded in a Cayley tree

The self-trapping transition due to a single and a dimer nonlinear impurity embedded in a Cayley tree is studied. In particular, the effect of a perfectly nonlinear Cayley tree is considered. A sharp self-trapping transition is observed in each case. It is also observed that the transition is much sharper compared to the case of one-dimensional lattices. For each system, the critical values of $\chi$ for the self-trapping transitions are found to obey a power-law behavior as a function of the connectivity $K$ of the Cayley tree.Comment: 6 pages, 7 fig

Andes Basin Focal Project

The CPWF Basin Focal Project for the Andes system of basins worked with a range of local stakeholders to develop a better understanding of the mechanisms for improving the productivity of water in the Andes. We considered productivity in broad terms as the productivity of energy (HEP), food and fiber (agriculture) and livelihoods (industry, transport and benefit sharing such as Payments for Environmental Services schemes (PES)). In addition to the compiled data bases and analyses on poverty and institutions, one of the key deliverables of the project was the development and deployment of the AguAAndes policy support system (PSS). This integrates analyses of water availability and productivity within the local environmental and policy context. It is a web-based policy support system combining an extensive spatial database with process-based models for hydrology, crop production and socio-economic processes. It is intended to allow analysts and decision makers to test the potential onsite and offsite impacts of land and water management decisions in terms of their ability to sustain environmental services and human wellbeing. Interventions and recommendations for future actions on water and food in the region are presented

Chaetopterid tubes from vent and seep sites: Implications for fossil record and evolutionary history of vent and seep annelids

Vestimentiferan tube worms living at deep-sea hydrothermal vents and cold seeps have been considered as a clade with a long and continuing evolutionary history in these ecosystems. Whereas the fossil record appears to support this view, molecular age estimates do not. The two main features that are used to identify vestimentiferan tubes in the fossil record are longitudinal ridges on the tube's surface and a tube wall constructed of multiple layers. It is shown here that chaetopterid tubes from modern vents and seeps—as well as a number of fossil tubes from shallow-water environments—also show these two features. This calls for a more cautious interpretation of tubular fossils from ancient vent and seep deposits. We suggest that: current estimates for a relatively young evolutionary age based on molecular clock methods may be more reliable than the inferences of ancient “vestimentiferans” based on putative fossils of these worms; not all of these putative fossils actually belong to this group; and that tubes from fossil seeps should be investigated for chitinous remains to substantiate claims of their potential siboglinid affinities

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

Analysis of shared heritability in common disorders of the brain

Paroxysmal Cerebral Disorder

Blowdown heat transfer separate-effects program. Quarterly progress report, January-March 1980

Six additional bundle uncovery/recovery tests were performed in the Thermal-Hydraulic Test Facility during January, bringing the total number of these tests to eight. Data taken during the tests were found to be contaminated by numerous spurious spikes. Work to remove the spurious spikes is under way. Posttest analysis of the tests is approx.20% completed. The recovery portion of one of the tests will be analyzed by COBRA/TRAC, currently being developed by Pacific Northwest Laboratories (PNL). Work to debug the code for this application is in progress at PNL. The uncovery/recovery tests apparently caused damage to the 0-rings that form part of the loop pressure boundary. Refurbishment of the 0-ring seal system is being performed concurrently with scheduled loop modifications that include installation of ten in-bundle differential pressure instruments. Design, procurement, and fabrication of the in-bundle gamma densitometer system are continuing on schedule