A Low-Noise Electrically Levitated Oscillator for Investigating Fundamental Physics

This thesis describes the creation of a low-noise, electrodynamically levitated nanoparticle oscillator for applications in optomechanics and quantum physics. The harmonic motion of a nanoparticle trapped in a linear Paul trap was measured and characterized. Velocity damping and parametric feedback cooling methods were implemented to cool the centre-of-mass motion of an oscillator. Experiments were conducted on the same particle so that a direct comparison between both methods could be done. Theory and simulations were developed to fully understand these processes. It was shown that velocity damping achieves lower temperatures due to the greater backaction from measurement noise in the parametric feedback scheme. A minimum temperature of $26\pm6$\,mK was reached in these experiments limited only by detection noise. Low-noise electronics, designed to prevent motional heating of the levitated nanoparticle due to fluctuations in the confining electric fields, were studied. At low pressures down to 3×10⁻⁷ mbar, where minimal thermal noise is present from gas collisions, no heating effect from voltage fluctuations was observed in two of the oscillator modes. This work demonstrated the utility of this trap for future low-noise experiments including investigations into wave function collapse with preliminary results presented here. The cooling and dynamics of two co-trapped nanoparticles strongly coupled by their mutual Coulomb repulsion was also studied. The normal modes in both the axial and radial motion of the trapped nanoparticle were measured and characterized. Sympathetic cooling and squeezing of one particle were achieved through interaction with the other trapped nanoparticle. Temperatures down to 200±10 mK and 190±40 mK were reached in the axial normal modes. Additionally, a measurement-based scheme was used to couple the axial normal modes which were shown to display the characteristics of strong coupling. Energy exchange between the two modes was demonstrated alongside sympathetic cooling of one mode through this coupling

From Australia to Africa, fences are stopping Earth’s great animal migrations

Both of these enormous fences were intended to repel rabbits and other “vermin” such emus, kangaroos and dingoes that were considered threats to crops or livestock. Built over a century ago, their environmental impacts were poorly understood or disregarded at the tim

Playing the odds in clinical decision making: lessons from berry aneurysms undetected by magnetic resonance angiography

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Impact of a Professional Development Experience Focused on Extension Educators as Change Agents

Extension educators should think of themselves as change agents, yet many act as information dispensers. Accordingly, we sought to determine whether we could change perceptions of county Extension educators in Oklahoma regarding their function as change agents. Educators participated in a two-part (two-treatment) professional development experience involving a workshop and a computer simulation. The experience was grounded in Rogers\u27s diffusion of innovations theory and addressed nine established Extension educator change-agent roles. Participants ranked the importance of the roles prior to the experience and again following each treatment. Their perceptions changed regarding only the Alternative Delivery Systems role. We explore the imperative to improve Extension agents\u27 understanding of how to be change agents

Prednisolone therapy for chronic hepatitis in English springer spaniels: a prospective study of 12 cases.

BACKGROUND: English springer spaniels (ESS) show an increased risk of chronic hepatitis (CH). In a previous study of 68 ESS with CH, in which only one dog received corticosteroids, a median survival time of 189 days was noted. Some ESS with CH appear to improve with prednisolone treatment; therefore, we aimed to investigate the response to prednisolone in this breed. PARTICIPANTS: ESS with histologically confirmed idiopathic CH were treated with prednisolone 1-2 mg/kg/day. Nine female and three male ESS were enrolled (median age at diagnosis of five years). Patients were monitored clinically and had biochemistry samples taken to assess markers of hepatocellular damage and function. RESULTS: The mean starting dose of prednisolone was 1.1 mg/kg/day. All symptomatic patients showed an initial clinical improvement. Two cases were euthanased while receiving prednisolone. The median time since diagnosis is 1715 days (range: 672-2105 days) and the remaining patients are clinically well, with seven patients still receiving a mean dose of 0.4 mg/kg prednisolone every other day. Statistical analysis demonstrated significant (P<0.05) reductions in serum alkaline phosphatase, alanine aminotransferase and bilirubin following 2-4 weeks of prednisolone treatment. CONCLUSION: This study demonstrates improved clinical and biochemical parameters when some ESS with CH are managed with prednisolone and standard supportive treatments

Bismuth-Based Nanoparticles as Photocatalytic Materials

Bismuth-based nanoparticles are a unique category of materials that possess interesting properties such as excellent chemical, electrical, optical and catalytic activities among others. The application of bismuth-based nanoparticles as photocatalytic materials has caught the interest of the scientific community in recent times due to these unique properties. Consequently, a number of data have been generated in relation to the photocatalytic application of these nanoparticles. This chapter intends to organise and provide the recently generated information on the use of bismuth-based nanoparticles in photocatalytic degradation processes. A detailed discussion is provided on bismuth-based nanoparticles including bismuth chalcogenides, bismuth vanadate, bismuth oxyhalides and other bismuth-related nanoparticles. Attention was also paid to the modification of these nanoparticles to improve their photocatalytic activities. The application of the modified nanoparticles in various photocatalytic processes with emphasis on water treatment, waste gas treatment, hydrogen production and air purification has also been thoroughly discussed

Phenolic Compounds in Water: Sources, Reactivity, Toxicity and Treatment Methods

Phenolic compounds exist in water bodies due to the discharge of polluted wastewater from industrial, agricultural and domestic activities into water bodies. They also occur as a result of natural phenomena. These compounds are known to be toxic and inflict both severe and long‐lasting effects on both humans and animals. They act as carcinogens and cause damage to the red blood cells and the liver, even at low concentrations. Interaction of these compounds with microorganisms, inorganic and other organic compounds in water can produce substituted compounds or other moieties, which may be as toxic as the original phenolic compounds. This chapter dwells on the sources and reactivity of phenolic compounds in water, their toxic effects on humans, and methods of their removal from water. Specific emphasis is placed on the techniques of their removal from water with attention on both conventional and advanced methods. Among these methods are ozonation, adsorption, extraction, photocatalytic degradation, biological, electro‐Fenton, adsorption and ion exchange and membrane‐based separation