Cyclic Testing of Reinforced Earthbag Walls

Earthen construction is the most popular building method around the world. One particular building method, using earthbags, has shown promise in performing well against seismic activity. This project undertook the goal of developing a preliminary seismic response modification factor, R, to be used in the design of homes in seismically active areas. Two 4’ wide x 6’ tall x 1’ deep walls were cyclically loaded using a Three-Degree-of-Freedom (TDOF) Test Frame provided by Santa Clara University to determine the in-plane shear capacity of each wall. Testing revealed an average yield force of 419 lbs, an average ultimate force 1058 lbs, and an average R value of 6. Wall design and construction was focused on three aspects of the project that were modeled to replicate common building practices while still being modular enough to test multiple samples. These aspects were the base, bond beam, and wall. Wall bases were designed to withstand up to 3500 lb-ft bending moment during forklift transport, the bond beam was designed to transfer up to 9,000 lbs of shear force into the wall, and, the wall was designed using common building practices used in earthbag construction. Upon completion of the Consortium of Universities for the Research of Earthquake Engineering (CUREE) testing protocol, it was observed that the walls failed in buckling due to compression resulting from the force couple created by the loading arrangement. Despite failure, the walls continued standing even after the pin connection was removed from the tops of wall. This unexpected resiliency and behavior of the walls during testing led the team to believe that earthbag walls are much more ductile a material that was initially anticipated. A deeper understanding is needed to better understand how earthbag buildings behave against seismic forces. This project is encouraging for future research and the development of a more standardized building method

Comparative genomics of Shiga toxin encoding bacteriophages

Background Stx bacteriophages are responsible for driving the dissemination of Stx toxin genes (stx) across their bacterial host range. Lysogens carrying Stx phages can cause severe, lifethreatening disease and Stx toxin is an integral virulence factor. The Stx-bacteriophage vB_EcoP-24B, commonly referred to as 24B, is capable of multiply infecting a single bacterial host cell at a high frequency, with secondary infection increasing the rate at which subsequent bacteriophage infections can occur. This is biologically unusual, therefore determining the genomic content and context of 24B compared to other lambdoid Stx phages is important to understanding the factors controlling this phenomenon and determining whether they occur in other Stx phages. Results The genome of the Stx2 encoding phage, 24B was sequenced and annotated. The genomic organisation and general features are similar to other sequenced Stx bacteriophages induced from Enterohaemorrhagic Escherichia coli (EHEC), however 24B possesses significant regions of heterogeneity, with implications for phage biology and behaviour. The 24B genome was compared to other sequenced Stx phages and the archetypal lambdoid phage, lambda, using the Circos genome comparison tool and a PCR-based multi-loci comparison system. Conclusions The data support the hypothesis that Stx phages are mosaic, and recombination events between the host, phages and their remnants within the same infected bacterial cell will continue to drive the evolution of Stx phage variants and the subsequent dissemination of shigatoxigenic potentia

Pulsed laser deposition for growth of high quality epitaxial garnet films for low threshold waveguide lasers

Pulsed laser deposition (PLD) is a mature technique capable of producing extremely high quality epitaxial single crystalline films. We have grown Nd:doped garnet films of GGG (Gd The talk will summarise our progress using conventional (single beam) PLD in thin-film and waveguide growth, using both nanosecond and femtosecond lasers, and also introduce our new directions in tri-beam PLD (three targets, three lasers) for growth of some interesting, complex and perhaps impossible structures, such as Gaussian doping, internal voids and even helically doped structures

Do Public Transit Investments Promote Urban Economic Development? Evidence from Bogotá, Colombia

In this paper, the authors use a repeated cross-section labor market dataset to assess whether access to the TransMilenio Bus Rapid Transit (BRT) system in Bogotá, Colombia, affects the incomes of those who live in station area neighborhoods. Results indicate that the opening of the system was associated with increased income for those living near – but not immediately adjacent to – trunk line stations. This relationship is strongest in the lower and middle-income range. Two possible explanations for this result are that existing residents earn higher wages, or higher income workers relocate to the neighborhood. While available data do not allow the authors to distinguish clearly between these two causes, evidence suggests that much of the effect is likely due to relocation. The results stand in contrast to prior work, which has largely suggested that improvements in public transit will tend to reduce wages in station areas

First results of the SOAP project. Open access publishing in 2010

The SOAP (Study of Open Access Publishing) project has compiled data on the present offer for open access publishing in online peer-reviewed journals. Starting from the Directory of Open Access Journals, several sources of data are considered, including inspection of journal web site and direct inquiries within the publishing industry. Several results are derived and discussed, together with their correlations: the number of open access journals and articles; their subject area; the starting date of open access journals; the size and business models of open access publishers; the licensing models; the presence of an impact factor; the uptake of hybrid open access.Comment: Submitted to PLoS ON

Draft Genome Sequence of the Bactrocera oleae Symbiont "Candidatus Erwinia dacicola".

"Candidatus Erwinia dacicola" is a Gammaproteobacterium that forms a symbiotic association with the agricultural pest Bactrocera oleae Here, we present a 2.1-Mb draft hybrid genome assembly for "Ca. Erwinia dacicola" generated from single-cell and metagenomic data