Involving the public in restoring the role of fire in the longleaf pine ecosystem of Upland Island Wilderness

The 13,250-acre Upland Island Wilderness (UIW) in Texas was established in 1984 and is managed by the United States Forest Service (USFS). Historically, portions of it consisted of open and diverse longleaf pine (Pinus palustris) ecosystems which depend on frequent, low-intensity surface fires. As in many other relatively small wilderness areas, the vegetation and fuel conditions in the UIW underwent extensive changes after wilderness designation. Lightning-caused wildfires were no longer allowed to burn with the frequency or intensity that characterized the natural fire regime. This has resulted in an increase of shade-tolerant trees and shrubs, heavy accumulations of duff and pine litter, and loss of suitable habitat for several rare species, including the red-cockaded woodpecker (Picoides borealis). In addition, the unnatural fuel accumulations have created a serious fire hazard that threatens the safety of firefighters, private citizens, adjacent properties, and the wilderness resource itself

Correlating bacterial shedding with fecal corticosterone levels and serological responses from layer hens experimentally infected with Salmonella Typhimurium

Salmonella Enteriditis and Salmonella Typhimurium are commonly isolated during egg-related outbreaks of salmonellosis and represent a significant international public health issue. In Australia, Salmonella Typhimurium is the most common serovar identified in egg product related foodborne outbreaks. While a number of studies have investigated Salmonella shedding and host responses to infection, they have been conducted over a short time period. The present study sought to characterise bacterial shedding and host responses to infection in hens infected with only Salmonella Typhimurium or co-infected with both Salmonella Typhimurium and Salmonella Mbandaka over a 16 week period. Salmonella shedding was quantified using the most probable number and qPCR methods and was highly variable over the course of the experiment. On day 1, fecal corticosterone metabolites in birds infected with Salmonella Typhimurium (674.2 ± 109.3 pg/mg) were significantly higher than control (238.0 ± 12.62 pg/mg) or co-infected (175.4 ± 8.58 pg/mg) birds. The onset of lay occurred between weeks 6-8 post-infection (pi) and Fecal corticosterone metabolite (FCM) concentrations increased in both control and co-infected birds. Antibody responses to infection were monitored in both serum and yolk samples. Salmonella Typhimurium specific antibody was lower in co-infected animals than monoinfected animals. Bacterial loads in internal organs were characterised to determine persistence. Spleen, liver and caecal tonsils were positive for bacteria in both groups, indicating that Salmonella was not cleared from the birds and internal organ colonization could serve as a reservoir for continued bacterial shedding.Pardeep Sharma, Vivek V. Pande, Talia S. Moyle, Andrea R. McWhorter and Kapil K. Chousalka

Teaching in the COVID-19 era: Understanding the opportunities and barriers for teacher agency

The school closures necessitated by the COVID-19 pandemic created a rapid shift to alternative modes of educational delivery, primarily online learning and teacher-supported home-schooling. This shift has revealed deep inequities in education systems worldwide, as many children lost access to teachers and schooling. An effective response to these changes has tested teachers’ personal capacities and individual and collective agency intensely. The research lab we report on within this paper aimed to develop a better understanding of teacher agency in meeting the challenges of the pandemic and the physical and relational enablers and constraints of their environment. Drawing on case study reports from six international contexts and a series of online discussions with research lab participants, this study explores teachers’ enactment of agency in the context of various circumstances and environments. The authors argue that it is imperative that education systems support the enhancement of teachers’ personal and collective agency in the face of continued disruption to schooling and ongoing challenges to educational equity

Salmonella Typhimurium in the Australian egg industry: multidisciplinary approach to addressing the public health challenge and future directions

In Australia, numerous egg related human Salmonella Typhimurium outbreaks have prompted significant interest amongst public health authorities and the egg industry to jointly address this human health concern. Nationwide workshops on Salmonella and eggs were conducted in Australia for egg producers and regulatory authorities. State and National regulators representing Primary Production, Communicable Disease Control, Public Health and Food Safety and Food Standards Australia and New Zealand. All attendees participated in discussions aimed at evaluating current evidence based information, issues related to quality egg production and how to ensure safe eggs in the supply chain, identifying research gaps and practical recommendations. The perceptions from egg producers and regulatory authorities from various states were recorded during the workshops. We presented the issues discussed during the workshops including Salmonella in the farm environment, Salmonella penetration across egg shell, virulence in humans, food/egg handling in the supply chain and intervention strategies. We also discussed the perceptions from egg producers and regulators. Recommendations placed emphasis on future research needs, communication between industry and regulatory authorities and education of food handlers. Communication between regulators and industry is pivotal to control egg borne S. Typhimurium outbreaks and collaborative efforts are required to design effective and appropriate control strategies.Kapil K. Chousalkar, Margaret Sexton, Andrea McWhorter, Kylie Hewson, Glen Martin, Craig Shadbolt & Paul Goldsmit

The Growing Necessity for Continuing Education: The Short Course Option

Continuing education is a critical issue in the workplace. Rapid change, the emergence of new technology, and the lack of trained individuals make continuing education an imperative for employers. The desire for individual growth and marketability make it an imperative for the employee also. While there are many options for continuing education, an increasingly popular vehicle is the short course. Time, cost efficiency and instruction by those experienced in real industrial practice are key factors in the success of this educational format. Over the past couple of decades, short course offerings and the number and type of sponsoring organizations have grown significantly. Within the scientific community, courses in basic disciplines (e.g., materials characterization), emergent technologies (e.g., Micro-Electro- Mechanical Systems), equipment operation (e.g., electron microscopes) and even business practices (e.g., ES&H, proposal writing) have emerged and are taught by universities, technical societies and equipment manufacturers. Short course offerings and formats are evolving. Presently, it is possible to find series of courses which define specific curricula. These curricula set the stage for new developments in the future, including increased certification and licensing (e.g., technologists). Along with such certifications will come the need for accreditation. Who will offer such programs, and especially, who will accredit them are significant questions. Perhaps the most dramatic changes will occur with the integration of advanced information technology. While satellite-based remote offerings are available, the use of the web for educating a dispersed group is just beginning to emerge. In its simplest forms, this offers little advantage over a video or a real-time satellite course, but the eventual emergence of tele-operation of experimental equipment will revolutionize remote teaching

Mistletoebirds and xylose: Australian frugivores differ in their handling of dietary sugars

Carbohydrate-rich mistletoe fruits are consumed by a wide range of avian species. Small birds absorb a large portion of water-soluble nutrients, such as glucose, via the paracellular pathway. d-xylose, a pentose monosaccharide, is abundant in some nectars and mistletoe fruits consumed by birds, and it has been suggested that it is most likely absorbed via the paracellular pathway in birds. We measured apparent assimilation efficiency (AE*) and bioavailability (f) for d-xylose and d- and l-glucose in three frugivorous Australian bird species. Mistletoebirds, silvereyes, and singing honeyeaters showed significantly lower AE* for d-xylose than for d-glucose. Across two diet sugar concentrations, silvereyes and singing honeyeaters significantly increased(f)of both l-glucose (a metabolically inert isomer of d-glucose commonly used to quantify paracellular uptake) and d-xylose on the more concentrated diet, probably because of increased gut processing time. By contrast, mistletoebirds (mistletoe fruit specialists) did not vary (f) of either sugar with diet concentration. Mistletoebirds also showed higher (f) for d-xylose than l-glucose and eliminated d-xylose more slowly than silvereyes and singing honeyeaters, demonstrating differences in the handling of dietary xylose between these species. Our results suggest that d-xylose may be absorbed by both mediated and nonmediated mechanisms in mistletoebirds.Kathryn R. Napier, Patricia A. Fleming, Todd J. McWhorte

Universal 1/f Noise from Dissipative SOC Models

We introduce a model able to reproduce the main features of 1/f noise: hyper-universality (the power-law exponents are independent on the dimension of the system; we show here results in d=1,2) and apparent lack of a low-frequency cutoff in the power spectrum. Essential ingredients of this model are an activation-deactivation process and dissipation.Comment: 3 Latex pages, 2 eps Figure

Electrical and Noise Characteristics of Graphene Field-Effect Transistors: Ambient Effects and Noise Sources

We fabricated a large number of single and bilayer graphene transistors and carried out a systematic experimental study of their low-frequency noise characteristics. A special attention was given to determining the dominant noise sources in these devices and the effect of aging on the current-voltage and noise characteristics. The analysis of the noise spectral density dependence on the area of graphene channel showed that the dominant contributions to the low-frequency electronic noise come from the graphene layer itself rather than from the contacts. Aging of graphene transistors due to exposure to ambient for over a month resulted in substantially increased noise attributed to the decreasing mobility of graphene and increasing contact resistance. The noise spectral density in both single and bilayer graphene transistors either increased with deviation from the charge neutrality point or depended weakly on the gate bias. This observation confirms that the low-frequency noise characteristics of graphene transistors are qualitatively different from those of conventional silicon metal-oxide-semiconductor field-effect transistors.Comment: 26 pages with 8 figure

Friction in surface micromachined microengines

Understanding the frictional properties of advanced Micro-Electro- Mechanical Systems (MEMS) is essential in order to develop optimized designs and fabrication processes, as well as to qualify devices for commercial applications. We develop and demonstrate a method to experimentally measure the forces associated with sliding friction of devices rotating on a hub. The method is demonstrated on the rotating output gear of the microengine recently developed at Sandia National Laboratories. In-situ measurements of an engine running at 18300 rpm give a coefficient of friction of 0.5 for radial (normal) forces less than 4 {mu}N. For larger forces the effective coefficient of friction abruptly increases, suggesting a fundamental change in the basic nature of the interaction between the gear and hub. The experimental approach we have developed to measure the frictional forces associated with the microengine is generically applicable to other MEMS devices