Frequency shifts and depth dependence of premotor beta band activity during perceptual decision-making

Neural activity in the premotor and motor cortices shows prominent structure in the beta frequency range (13–30 Hz). Currently, the behavioral relevance of this beta band activity (BBA) is debated. The underlying source of motor BBA and how it changes as a function of cortical depth are also not completely understood. Here, we addressed these unresolved questions by investigating BBA recorded using laminar electrodes in the dorsal premotor cortex of 2 male rhesus macaques performing a visual reaction time (RT) reach discrimination task. We observed robust BBA before and after the onset of the visual stimulus but not during the arm movement. While poststimulus BBA was positively correlated with RT throughout the beta frequency range, prestimulus correlation varied by frequency. Low beta frequencies (∼12–20 Hz) were positively correlated with RT, and high beta frequencies (∼22–30 Hz) were negatively correlated with RT. Analysis and simulations suggested that these frequency-dependent correlations could emerge due to a shift in the component frequencies of the prestimulus BBA as a function of RT, such that faster RTs are accompanied by greater power in high beta frequencies. We also observed a laminar dependence of BBA, with deeper electrodes demonstrating stronger power in low beta frequencies both prestimulus and poststimulus. The heterogeneous nature of BBA and the changing relationship between BBA and RT in different task epochs may be a sign of the differential network dynamics involved in cue expectation, decision-making, motor preparation, and movement execution.Published versio

Molecular interactions between Mycoplasma hyopneumoniae and host cells

University of Technology Sydney. Faculty of Science.The Mycoplasmas are a group of wall-less bacteria belonging to the Mollicutes that are believed to have diverged from the Gram-positive Firmicutes. Mollicutes have undergone reductive evolution, losing genes for the biosynthesis of essential biomolecules, subsequently having to form parasite relationships with their hosts in order to acquire these nutrients. They form these relationships as both commensals and pathogens, and a number of Mycoplasma species cause significant clinical and agricultural diseases. Mycoplasma hyopneumoniae is the causative agent of porcine enzootic pneumonia, a chronic respiratory disease that affects swine populations worldwide. M. hyopneumoniae colonises the upper respiratory tract by adhering to the rapidly beating cilia where it causes ciliostasis and eventual cilial death [1]. M. hyopneumoniae possesses a family of surface adhesins referred to as the P97 and P102 paralog family that it utilises to adhere to the cilia [2-10]. A hallmark of M. hyopneumoniae infection is a potent inflammatory response which is believed to be one of the contributing factors to the gross lung lesions observed in infected swine [11-13]. M. hyopneumoniae is described as a strict extracellular pathogen that only adheres to cilia and knowledge is lacking on additional receptors that M. hyopneumoniae binds to. Recent studies have however, shown that viable M. hyopneumoniae cells can be cultured from the liver, spleen, kidneys and lymph nodes of infected swine [14-16]. These observations suggest that M. hyopneumoniae has the capability to invade through the epithelial barrier and disseminate to distal tissue sites. In addition to this, large microcolonies have been observed in the respiratory tract of swine infected with M. hyopneumoniae [17]. These microcolonies are reminiscent of biofilms, and although biofilm formation has never been investigated in M. hyopneumoniae it is likely that they play a role in the chronicity of disease. Notably, even when lung lesions in M. hyopneumoniae-infected swine are cleared, bronchial swabs can still test positive for M. hyopneumoniae up to 185 days post-infection (P.I.) [18] and pigs can act as convalescent carriers for up to 200 days P.I. [19]. This suggests that M. hyopneumoniae possesses mechanisms in which it can remain dormant within its host whilst remaining infectious. Vaccines against M. hyopneumoniae can successfully reduce lung lesions but they are unable to prevent transmission in swine herds [20]. In order to create vaccines that inhibit the transmission of M. hyopneumoniae, a better understanding of the disease process is required. This PhD project has thus been devised in order to address the problems outlined above. This work has investigated the ability of adhesins to undergo extensive endoproteolytic processing; demonstrating that proteolytic processing in the P97 and P102 adhesins occurs much more extensively than what has previously been shown. I also show that these adhesins can bind to a myriad of host components such as heparin, fibronectin (Fn) and plasminogen (Plg) and investigate the domains responsible. Additionally, this work presents a number of novel receptors that M. hyopneumoniae targets within its host as well as a comprehensive list of putative adhesins that it utilises to do so. This work has also investigated the ability of M. hyopneumoniae to form biofilms on abiotic surfaces, host cells and within the swine respiratory tract and further demonstrate that surface adhesins play a role in biofilm formation. A number of putative biofilm-associated genes have been identified by screening a transposon mutant library, these genes being potential vaccine candidates. Finally, this work has investigated the ability of M. hyopneumoniae to become internalised by host cells and reside within the cytoplasm. M. hyopneumoniae becomes internalised by vacuole-like structures, and that internalised cells appear to escape from lysosomes to reside free within the cytoplasm. Overall, this PhD project has contributed significantly to understanding how M. hyopneumoniae causes disease. Future work on the novel mechanisms described in this thesis will aid in future vaccine development programs and potentially aid in the control of this important veterinary disease

The effect of South American biomass burning aerosol emissions on the regional climate

The impact of biomass burning aerosol (BBA) on the regional climate in South America is assessed using 30-year simulations with a global atmosphere-only configuration of the Met Office Unified Model. We compare two simulations of high and low emissions of biomass burning aerosol based on realistic interannual variability. The aerosol scheme in the model has hygroscopic growth and optical properties for BBA informed by recent observations, including those from the recent South American Biomass Burning Analysis (SAMBBA) intensive aircraft observations made during September 2012. We find that the difference in the September (peak biomass emissions month) BBA optical depth between a simulation with high emissions and a simulation with low emissions corresponds well to the difference in the BBA emissions between the two simulations, with a 71.6 % reduction from high to low emissions for both the BBA emissions and the BB AOD in the region with maximum emissions (defined by a box of extent 5–25° S, 40–70° W, used for calculating mean values given below). The cloud cover at all altitudes in the region of greatest BBA difference is reduced as a result of the semi-direct effect, by heating of the atmosphere by the BBA and changes in the atmospheric stability and surface fluxes. Within the BBA layer the cloud is reduced by burn-off, while the higher cloud changes appear to be responding to stability changes. The boundary layer is reduced in height and stabilized by increased BBA, resulting in reduced deep convection and reduced cloud cover at heights of 9–14 km, above the layer of BBA. Despite the decrease in cloud fraction, September downwelling clear-sky and all-sky shortwave radiation at the surface is reduced for higher emissions by 13.77 ± 0.39 W m−2 (clear-sky) and 7.37 ± 2.29 W m−2 (all-sky), whilst the upwelling shortwave radiation at the top of atmosphere is increased in clear sky by 3.32 ± 0.09 W m−2, but decreased by −1.36±1.67 W m−2 when cloud changes are included. Shortwave heating rates increase in the aerosol layer by 18 % in the high emissions case. The mean surface temperature is reduced by 0.14 ± 0.24 °C and mean precipitation is reduced by 14.5 % in the peak biomass region due to both changes in cloud cover and cloud microphysical properties. If the increase in BBA occurs in a particularly dry year, the resulting reduction in precipitation may exacerbate the drought. The position of the South Atlantic high pressure is slightly altered by the presence of increased BBA, and the strength of the southward low-level jet to the east of the Andes is increased. There is some evidence that some impacts of increased BBA persist through the transition into the monsoon, particularly in precipitation, but the differences are only statistically significant in some small regions in November. This study therefore provides an insight into how variability in deforestation, realized through variability in biomass burning emissions, may contribute to the South American climate, and consequently on the possible impacts of future changes in BBA emissions

Thienoisoindigo-Based Semiconductor Nanowires Assembled with 2-Bromobenzaldehyde via Both Halogen and Chalcogen Bonding

We fabricated nanowires of a conjugated oligomer and applied them to organic field-effect transistors (OFETs). The supramolecular assemblies of a thienoisoindigo-based small molecular organic semiconductor (TIIG-Bz) were prepared by co-precipitation with 2-bromobenzaldehyde (2-BBA) via a combination of halogen bonding (XB) between the bromide in 2-BBA and electron-donor groups in TIIG-Bz, and chalcogen bonding (CB) between the aldehyde in 2-BBA and sulfur in TIIG-Bz. It was found that 2-BBA could be incorporated into the conjugated planes of TIIG-Bz via XB and CB pairs, thereby increasing the pi - pi stacking area between the conjugated planes. As a result, the driving force for one-dimensional growth of the supramolecular assemblies via pi - pi stacking was significantly enhanced. TIIG-Bz/2-BBA nanowires were used to fabricate OFETs, showing significantly enhanced charge transfer mobility compared to OFETs based on pure TIIG-Bz thin films and nanowires, which demonstrates the benefit of nanowire fabrication using 2-BB

Characterization of pea starch-guar gum biocomposite edible films enriched by natural antimicrobial agents for active food packaging

Antimicrobial activity of epigallocatechin-3-gallate (EGCG) and two native Australian plants blueberry ash (BBA) fruit and macadamia (MAC) skin extracts against nine pathogenic and spoilage bacteria and seven strains of fungi, using an agar well diffusion assay were investigated. The minimum inhibitory concentrations (MIC) of these compounds were calculated using 96-well microtiter plates method. Finally, active antimicrobial packaging films were prepared by incorporation of EGCG, BBA and MAC extracts at 1-, 2-, 3-, and 4-fold of their correspondence MIC values into edible films based on pea starch and guar gum (PSGG). The antimicrobial activity of films was investigated against target microorganisms by agar disc diffusion technique and quantified using the viable cell count assay. Among the test microorganisms, Salmonella typhimurium and Rhizopus sp. were the most resistance to active films. Films containing EGCG showed the highest activity against all test strains. As the concentration of compounds increased higher than 2 × MIC, the mechanical characteristics of the films were affected considerably. The results indicated that EGCG-PSGG, BBA-PSGG and MAC-PSGG films can be used as active food packaging systems for preserving food safety and prolonging the shelf-life of the packaged food

Principles of information packaging in Baatonum (Gur)

This talk presents a study on information structure in the under-documented Gur language Baatonum (Bénin and Nigeria, language code bba)

Temporal and spectral variation of desert dust and biomass burning aerosol scenes from 1995?2000 using GOME

International audienceGlobal Ozone Monitoring Experiment (GOME) Absorbing Aerosol Index (AAI) and AAI-related residue data were used to investigate areas with UV-absorbing aerosols. Time series of regionally averaged residues show the seasonal variation and trends of aerosols and clouds in climatologically important parts of the globe. GOME spectra were used to study scenes containing specific types of aerosols. AAI data are specifically sensitive to biomass burning aerosols (BBA) and desert dust aerosols (DDA). Areas where these aerosols are regularly found were analysed to find spectral fingerprints in the ultraviolet (UV), visible and near-infrared (near-IR), to establish an aerosol type classification of BBA and DDA. Spectral residues are different for BBA and DDA, but over deserts the surface albedo is dominant beyond the UV and spectral residues cannot be used over land. Over oceans, about half of the BBA scenes show a very high reflectance that is never observed for DDA scenes. However, in the case of low reflectance scenes BBA and DDA cannot be distinguished. This is in part due to the microphysical and optical properties of biomass burning aerosols, which are highly variable in time, making it difficult to specify them spectrally as one type. Because of their high hygroscopicity BBA are often found in the presence of clouds, which disturb the spectrum of the scenes. Desert dust aerosols are much less hygroscopic and behave spectrally more uniformly

Making the Mechanism of Enterprise Performance Management

This paper is devoted to the development and methodological ground of a conception of making the mechanism of enterprise performance management. It describes a model of implementation of performance benchmarking on the enterprise includes the sequence of operations, which enables to connect together several key management functions, and clearly divide the performance management process into several steps. It provides both direct and feedback to ensure continuity of performance management process. Author proposes an organizational mechanism to reduce the time and resources to implement the process of enterprise performance management that consists in an organization of the branch and regional benchmarking agencies (BBA and RBA). The BBA and RBA systems are functionally complement each other, and contribute to the accelerated development of various industries and regions: RBA increases the level of innovation development of efficient enterprises; BBA raises to this level remaining, less-efficient enterprises of the industry.benchmarking agency, economic efficiency, organizational mechanism, performance benchmarking, performance management.