Wheat diseases in Western Australia

DISEASES caused by pathogenic organisms can seriously affect the yield of wheat. Some diseases are comparatively rare whereas others occur over a large area of the wheatbelt year after year

Frequency doubling in the cyanobacterial circadian clock

Organisms use circadian clocks to generate 24-h rhythms in gene expression. However, the clock can interact with other pathways to generate shorter period oscillations. It remains unclear how these different frequencies are generated. Here, we examine this problem by studying the coupling of the clock to the alternative sigma factor $\textit{sigC}$ in the cyanobacterium $\textit{Synechococcus elongatus}$. Using single-cell microscopy, we find that $\textit{psbAI}$, a key photosynthesis gene regulated by both $\textit{sigC}$ and the clock, is activated with two peaks of gene expression every circadian cycle under constant low light. This two-peak oscillation is dependent on $\textit{sigC}$, without which $\textit{psbAI}$ rhythms revert to one oscillatory peak per day. We also observe two circadian peaks of elongation rate, which are dependent on $\textit{sigC}$, suggesting a role for the frequency doubling in modulating growth. We propose that the two-peak rhythm in $\textit{psbAI}$ expression is generated by an incoherent feedforward loop between the clock, $\textit{sigC}$ and $\textit{psbAI}$. Modelling and experiments suggest that this could be a general network motif to allow frequency doubling of outputs.This research was made possible by the award of a European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement 338060. The work in the Locke laboratory is further supported by a fellowship from the Gatsby Foundation (GAT3272/GLC) and a Fellowship from the Human Frontier Science Program (CDA00068/2012)

Focused Schlieren flow visualization studies of multiple venturi fuel injectors in a high pressure combustor

Multiple venturi fuel injectors were used to obtain uniform fuel distributions, better atomization and vaporization in the premixing/prevaporizing section of a lean premixed/prevaporized flame tube combustor. A focused Schlieren system was used to investigate the fuel/air mixing effectiveness of various fuel injection configurations. The Schlieren system was focused to a plane within the flow field of a test section equipped with optical windows. The focused image plane was parallel to the axial direction of the flow and normal to the optical axis. Images from that focused plane, formed by refracted light due to density gradients within the flow field, were filmed with a high-speed movie camera at framing rates of 8,000 frames per second (fps). Three fuel injection concepts were investigated by taking high-speed movies of the mixture flows at various operating conditions. The inlet air temperature was varied from 600 F to 1000 F, and inlet pressures from 80 psia to 150 psia. Jet-A fuel was used typically at an equivalence ratio of 0.5. The intensity variations of the digitized Schlieren images were analytically correlated to spatial density gradients of the mixture flows. Qualitative measurements for degree of mixedness, intensity of mixing, and mixing completion time are shown. Various mixing performance patterns are presented with different configurations of fuel injection points and operating conditions

Fe-oxide grain coatings support bacterial Fe-reducing metabolisms in 1.7−2.0 km-deep subsurface quartz arenite sandstone reservoirs of the Illinois Basin (USA)

The Cambrian-age Mt. Simon Sandstone, deeply buried within the Illinois Basin of the midcontinent of North America, contains quartz sand grains ubiquitously encrusted with iron-oxide cements and dissolved ferrous iron in pore-water. Although microbial iron reduction has previously been documented in the deep terrestrial subsurface, the potential for diagenetic mineral cementation to drive microbial activity has not been well studied. In this study, two subsurface formation water samples were collected at 1.72 and 2.02 km, respectively, from the Mt. Simon Sandstone in Decatur, Illinois. Low-diversity microbial communities were detected from both horizons and were dominated by Halanaerobiales of Phylum Firmicutes. Iron-reducing enrichment cultures fed with ferric citrate were successfully established using the formation water. Phylogenetic classification identified the enriched species to be related to Vulcanibacillus from the 1.72 km depth sample, while Orenia dominated the communities at 2.02 km of burial depth. Species-specific quantitative analyses of the enriched organisms in the microbial communities suggest that they are indigenous to the Mt. Simon Sandstone. Optimal iron reduction by the 1.72 km enrichment culture occurred at a temperature of 40oC (range 20 to 60oC) and a salinity of 25 parts per thousand (range 25-75 ppt). This culture also mediated fermentation and nitrate reduction. In contrast, the 2.02 km enrichment culture exclusively utilized hydrogen and pyruvate as the electron donors for iron reduction, tolerated a wider range of salinities (25-200 ppt), and exhibited only minimal nitrate- and sulfate-reduction. In addition, the 2.02 km depth community actively reduces the more crystalline ferric iron minerals goethite and hematite. The results suggest evolutionary adaptation of the autochthonous microbial communities to the Mt. Simon Sandstone and carries potentially important implications for future utilization of this reservoir for CO2 injection

FDG-PET Quantification of Lung Inflammation with Image-Derived Blood Input Function in Mice

Dynamic FDG-PET imaging was used to study inflammation in lungs of mice following administration of a virulent strain of Klebsiella (K.) pneumoniae. Net whole-lung FDG influx constant (Ki) was determined in a compartment model using an image-derived blood input function. Methods. K. pneumoniae (~3 x 105 CFU) was intratracheally administered to six mice with 6 other mice serving as controls. Dynamic FDG-PET and X-Ray CT scans were acquired 24 hr after K. pneumoniae administration. The experimental lung time activity curves were fitted to a 3-compartment FDG model to obtain Ki. Following imaging, lungs were excised and immunohistochemistry analysis was done to assess the relative presence of neutrophils and macrophages. Results. Mean Ki for control and K. pneumoniae infected mice were (5.1 ± 1.2) ×10−3 versus (11.4 ± 2.0) ×10−3 min−1, respectively, revealing a 2.24 fold significant increase (P = 0.0003) in the rate of FDG uptake in the infected lung. Immunohistochemistry revealed that cellular lung infiltrate was almost exclusively neutrophils. Parametric Ki maps by Patlak analysis revealed heterogeneous inflammatory foci within infected lungs. Conclusion. The kinetics of FDG uptake in the lungs of mice can be noninvasively quantified by PET with a 3-compartment model approach based on an image-derived input function

Aptamer conjugated silver nanoparticles for the detection of interleukin 6

The controlled assembly of plasmonic nanoparticles by a molecular binding event has emerged as a simple yet sensitive methodology for protein detection. Metallic nanoparticles (NPs) coated with functionalized aptamers can be utilized as biosensors by monitoring changes in particle optical properties, such as the LSPR shift and enhancement of the SERS spectra, in the presence of a target protein. Herein we test this method using two modified aptamers selected for the protein biomarker interleukin 6, an indicator of the dengue fever virus and other diseases including certain types of cancers, diabetes, and even arthritis. IL6 works by inducing an immunological response within the body that can be either anti-inflammatory or pro-inflammatory. The results show that the average hydrodynamic diameter of the NPs as measured by Dynamic Light Scattering was ∼42 nm. After conjugation of the aptamers, the peak absorbance of the AgNPs shifted from 404 to 408 nm indicating a surface modification of the NPs due to the presence of the aptamer. Lastly, preliminary results were obtained showing an increase in SERS intensity occurs when the IL-6 protein was introduced to the conjugate solution but the assay will still need to be optimized in order for it to be able to monitor varying concentration changes within and across the desired range

The Impact of Sensitive Research on the Researcher: Preparedness and Positionality

There is currently limited research exploring the impact of undertaking sensitive or challenging research on the researcher, although some textbooks explore researcher preparedness. This article presents a discussion of the findings from a research project which engaged with the seldom heard voices of researchers themselves. The aim was to explore researchers’ experiences of undertaking research on sensitive topics, or with marginalized groups, as this can expose researchers to emotionally disturbing situations throughout data collection and analysis, which can be psychologically challenging. Although ethical codes of practice include discussion around protection of both the researcher and the participant, in practice, the ethics approval process rarely considers the impact of the proposed research on the researcher. Their experiences are therefore seldom acknowledged or heard, resulting in potential distress for the researcher. Semistructured interviews were undertaken with social science researchers from a range of discipline backgrounds and at different points in their research careers (n = 10). This article explores two themes emerging from the data: preparedness and positionality. It considers what these themes mean in terms of supporting researchers who encounter challenging research data, and issues related to supporting researcher reflexivity and the requirements for institutional support offered to researchers will also be considered

MARCH WET AVALANCHE PREDICTION AT BRIDGER BOWL SKI AREA, MONTANA

ABSTRACT: Few avalanche forecast models are tailored specifically for wet avalanche forecasting. Bridger Bowl (intermountain climate) is a good area to develop a wet avalanche probability model. The primary archived data consists of eight variables. The archived data for March from 1968 to 2001 (1996 data unavailable) were used to develop 68 predictor variables related to temperature, snowpack settlement, and precipitation. The original dataset was divided into days with snowfall in the past 48 hours (new snow) and days without (old snow). There were 33 significant old snow variables and 22 significant new snow variables. Six variables are common to both old and new snow. The best predictor variables for old and new snow are different. The variables were analyzed with binomial logistic regression to produce probability models for old snow and for new snow wet avalanche conditions. The old snow model uses the prediction day minimum temperature and the two-day change in total snow depth as predictor variables and has a 89% overall success rate. However, the majority of this success is due to correct prediction of days without wet avalanches (96% of all correct predictions). The new snow model uses the prediction day minimum temperature and three-day cumulative new snow water equivalent as predictor variables, but is less useful. The models are applicable only to Bridger Bowl. The numerical forecast models can be used as one of the tools in the forecasting toolbox but limited data and complexity of process require that the decisions about closure remain in the hands of the ski patrol

MARCH WET AVALANCHE PREDICTION AT BRIDGER BOWL SKI AREA, MONTANA

ABSTRACT: Few avalanche forecast models are tailored specifically for wet avalanche forecasting. Bridger Bowl (intermountain climate) is a good area to develop a wet avalanche probability model. The primary archived data consists of eight variables. The archived data for March from 1968 to 2001 (1996 data unavailable) were used to develop 68 predictor variables related to temperature, snowpack settlement, and precipitation. The original dataset was divided into days with snowfall in the past 48 hours (new snow) and days without (old snow). There were 33 significant old snow variables and 22 significant new snow variables. Six variables are common to both old and new snow. The best predictor variables for old and new snow are different. The variables were analyzed with binomial logistic regression to produce probability models for old snow and for new snow wet avalanche conditions. The old snow model uses the prediction day minimum temperature and the two-day change in total snow depth as predictor variables and has a 89% overall success rate. However, the majority of this success is due to correct prediction of days without wet avalanches (96% of all correct predictions). The new snow model uses the prediction day minimum temperature and three-day cumulative new snow water equivalent as predictor variables, but is less useful. The models are applicable only to Bridger Bowl. The numerical forecast models can be used as one of the tools in the forecasting toolbox but limited data and complexity of process require that the decisions about closure remain in the hands of the ski patrol

Recovery efficiency test project, Phase 2 activity report

The Recovery Efficiency Test well project addressed a number of technical issues. The primary objective was to determine the increased efficiency of gas recovery of a long horizontal wellbore over that of a vertical wellbore and, more specifically, what improvements can be expected from inducing multiple hydraulic fractures from such a wellbore. This volume contains appendices for: (1) supporting material and procedures for data frac'' stimulation of zone 6 using nitrogen and nitrogen foam; (2) supporting material and procedures for stimulation no. 1 nitrogen gas frac on zone no. 1; (3) supporting material and procedures for stimulation no. 2 in zone no. 1 using liquid CO{sub 2}; (4) supporting material and procedures for frac no. 3 on zone no.1 using nitrogen foam and proppant; (5) supporting material and procedures for stimulation no. 4 in zones 2--3 and 4 using nitrogen foam and proppant; (6) supporting materials and procedures for stimulation no. 5 in zones 5 and 8; and (7) fracture diagnostics reports and supporting materials