12,276 research outputs found
Restricted Maximum Likelihood Estimation of Variance Components for Univariate Animal Models Using Sparse Matrix Techniques and Average Information
The Extension Hedgehog
Extension is competing for money, attention, and a place in the future of higher education. It is critical that Extension identify its education niche, specialties, and the value that only Extension adds to learning. Extension must mature in its role by coordinating issues-based education from a total university base. Issues-based education is inherently collaborative and non-hierarchical. Extension should be at the forefront of the modern outreach and engagement movement. But what are we passionate about, what can we be the very best at in the world, and how do we effectively attach our work to its economic drivers
Adenine methylation and antimicrobial resistance
Development of antimicrobial resistance (AMR) continues to be a global concern. In order to minimise the impact of such it is imperative to gather as much data as possible on the mechanisms and key pathways involved. The aim of this project was to investigate the role of adenine methylation in the development of resistance to triclosan and associated antibiotic cross-resistance. Triclosan resistance was induced in E. coli through repeated exposure to sub-inhibitory concentrations. Pacbio SMRT sequencing was used to identify methylated bases in both wild type and resistance bacteria. Modified bases within genes were identified through genome annotation, and differentially methylated genes collated. E. coli rapidly became resistant to triclosan and exhibited increased resistance to multiple antibiotics. There were no statistically significant differences in global methylation. A number of genes associated with a range of functions were seen to be differentially methylated between the wild type and resistant cultures
The Ebola outbreak, 2013-2016: old lessons for new epidemics
Ebola virus causes a severe haemorrhagic fever in humans with high case fatality and significant epidemic potential. The 2013–2016 outbreak in West Africa was unprecedented in scale, being larger than all previous outbreaks combined, with 28 646 reported cases and 11 323 reported deaths. It was also unique in its geographical distribution and multicountry spread. It is vital that the lessons learned from the world's largest Ebola outbreak are not lost. This article aims to provide a detailed description of the evolution of the outbreak. We contextualize this outbreak in relation to previous Ebola outbreaks and outline the theories regarding its origins and emergence. The outbreak is described by country, in chronological order, including epidemiological parameters and implementation of outbreak containment strategies. We then summarize the factors that led to rapid and extensive propagation, as well as highlight the key successes, failures and lessons learned from this outbreak and the response
Human rights, non-refoulement and the protection of refugees in Hong Kong
Although the 1951 Convention relating to the Status of Refugees and its 1967 Protocol do not apply to Hong Kong, asylum seekers have challenged Hong Kong's lack of an adequate refugee policy in a series of judicial review actions grounded in human rights and common law principles. This article focuses on two cases in particular in which the applicants have attempted to rely, in part, on a right to non-refoulement, derived from international and domestic law, to compel the Government to establish procedures to determine the status of refugees and other similar categories of claimants. The first, Secretary for Security v. Sakthevel Prabakar, led to the creation of a 'torture screening' mechanism based on article 3 of the Convention against Torture and other Cruel, Inhuman, or Degrading Treatment or Punishment. In the second, C v. Director of Immigration, the court considered whether a rule of non-refoulement has emerged in customary international law and, if so, whether it applies to Hong Kong and requires government-administered refugee status determination. Although the applicants failed at first instance,1 an analysis of the judgment with reference to Hong Kong's human rights obligations reveals gaps in the court's reasoning and demonstrates the potential for greater reliance on these standards as the basis for developing a more comprehensive protection framework. This examination of the Hong Kong experience may have broader comparative value, especially in the Asian region and in jurisdictions not bound by the Refugee Convention or its Protocol. © The Author (2010). Published by Oxford University Press. All rights reserved.postprin
Laser Generation and Detection of Surface Acoustic Waves Using Gas-Coupled Laser Acoustic Detection
Laser generation and detection of ultrasound has the advantage of requiring no mechanical contact with the materials under investigation. We previously reported [1] laser-based measurements on Lamb waves in graphite/polymer composite laminates using a confocal Fabry-Perot interferometer for detection. Related work by other groups includes air-coupled detection of Lamb waves in similar composites using capacitive transducers [2,3] and interferometric detection of Lamb waves in paper [4]. Our earlier work has been extended using Gas-Coupled Laser Acoustic Detection (GCLAD), an economical alternative laser-based method which has the additional advantage that the detection laser beam is not reflected from the sample surface. GCLAD is thus particularly useful for materials with surfaces of poor optical quality. We demonstrate below that the combination of laser generation and GCLAD can be used to obtain well-resolved surface-acoustic waves (SAWs) in a variety of materials, including metals, paper, thin films, and composite pre-preg tape. We also show some preliminary SAW scans obtained with laser generation and GCLAD using metallic samples. Each pixel in the scans represents the strength of a SAW passing through a portion of the sample with an area of about 1 cm2. Scans of this type offer the possibility of economical testing of large sample areas, potentially on-line in a manufacturing environment
Ultrasonic Wave Dispersion and Attenuation in Fluid Filled Porous Media
The study of ultrasonic wave propagation in granular materials can lead to a better understanding of wave interaction with such materials as uncured cement and concrete. The measured parameters can then be used to investigate the curing process in particular the time required for a given mixture to consolidate. The cohesionless granular materials having loose contact between the constituent grains form a matrix that has negligible shear modulus. Sediment, sandy ground and concrete before solidification can be considered as examples of cohesionless granular materials. The shear and rigidity moduli of these materials can differ greatly from the values obtained by effective medium theories. In particular these differences could affect the ultrasonic wave propagation in such a material. In the case of cohesionless granular material the complete description of mechanical properties requires the consideration of discrete nature of the solid frame and the contact areas between the grains. Therefore wave interaction with such a material should also include the above mentioned effects. The goal of this work is to investigate the ultrasonic wave dispersion and attenuation in cohesionless granular materials the results can be to applied to the monitoring of cement and concrete during the curing process
Epiparasitic plants specialized on arbuscular mycorrhizal fungi
Over 400 non-photosynthetic species from 10 families of vascular plants obtain their carbon from fungi and are thus defined as myco-heterotrophs. Many of these plants are epiparasitic on green plants from which they obtain carbon by 'cheating' shared mycorrhizal fungi. Epiparasitic plants examined to date depend on ectomycorrhizal fungi for carbon transfer and exhibit exceptional specificity for these fungi, but for most myco-heterotrophs neither the identity of the fungi nor the sources of their carbon are known. Because many myco-heterotrophs grow in forests dominated by plants associated with arbuscular mycorrhizal fungi (AMF; phylum Glomeromycota), we proposed that epiparasitism would occur also between plants linked by AMF. On a global scale AMF form the most widespread mycorrhizae, thus the ability of plants to cheat this symbiosis would be highly significant. We analysed mycorrhizae from three populations of Arachnitis uniflora (Corsiaceae, Monocotyledonae), five Voyria species and one Voyriella species (Gentianaceae, Dicotyledonae), and neighbouring green plants. Here we show that non-photosynthetic plants associate with AMF and can display the characteristic specificity of epiparasites. This suggests that AMF mediate significant inter-plant carbon transfer in nature
Surface Wave Inspection of Porous Ceramics and Rocks
The most interesting feature of acoustic wave propagation in fluid-saturated porous media is the appearance of a second compressional wave, the so-called slow compressional wave, in addition to the conventional P (or fast) wave and the shear wave [1,2]. The slow compressional wave is essentially the motion of the fluid along the tortuous paths in the porous frame. This motion is strongly affected by viscous coupling between the fluid and the solid. Therefore, both the velocity and the attenuation of the slow wave greatly depend on the dynamic permeability of the porous frame. It was not until 1980, that Plona first experimentally observed the slow compressional wave in water-saturated porous ceramics at ultrasonic frequencies [3]. Only three years later, Feng and Johnson predicted the existence of a new slow surface mode on a fluid/fluid-saturated solid interface in addition to the well-known leaky-Rayleigh and true Stoneley modes [4,5]. The slow surface mode is basically the interface wave equivalent of the slow bulk mode, but there is a catch: the surface pores of the solid have to be closed so that this new mode can be observed. Otherwise, a surface vibration can propagate along the fluid/fluid-saturated porous solid interface without really moving the fluid since it can flow through the open pores without producing any significant reaction force. All previous efforts directed at the experimental observation of this new surface mode failed because of the extreme difficulty of closing the surface pores without closing all the pores close to the surface (e. g., by painting). On the other hand, it has been recently shown that surface tension itself could be sufficient to produce essentially closed-pore boundary conditions at the interface between a porous solid saturated with a wetting fluid, such as water or alcohol, and a non-wetting superstrate fluid, like air [6]
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