Atomization of synthetic and real samples using heated graphite atomizers for atomic absorption spectroscopy : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Chemistry at Massey University

The interference effects caused by a number of matrices including compounds such as NaC1, HC1, KBr, HNO3, H3PO4, H2SO4 on Cu, Pb, Cd and A1 atomic absorption signals when the elements are atomized from three non-flame graphite atomizers (furnace, cup and rod) are studied over several concentration ranges. Investigations show that most of the interferences found occur in the vapour phase. A comprehensive literature survey has been done and from this survey and the experimental work carried out, discussions are presented on the postulated mechanisms of interference. Two main theories are given for the vapour phase interference, i) entrapment of the atom in the matrix particle forming in the vapour, ii) rapid molecular condensation in the vapour phase. Several degrees of interference (both enhancement and depression) were obtained for the different chemical and atomization systems used. Attempts were made at rationalizing the degree and type of interference in terms of the postulated models. Supporting evidence for the atom entrapment theory was gained from an investigation of the nature of the non-atomic absorption peak obtained mainly when a1ka1i halides are present in the sample. Evidence is produced showing that the absorption spectra obtained from alkali halides here and by other workers are charge-transfer spectra. An investigation into the use of a graphite atomizer for zinc ana1ysis in bovine serum is presented and compared to determinations using flame atomic absorption on the same samples

High-resolution mapping of cancer cell networks using co-functional interactions.

Powerful new technologies for perturbing genetic elements have recently expanded the study of genetic interactions in model systems ranging from yeast to human cell lines. However, technical artifacts can confound signal across genetic screens and limit the immense potential of parallel screening approaches. To address this problem, we devised a novel PCA-based method for correcting genome-wide screening data, bolstering the sensitivity and specificity of detection for genetic interactions. Applying this strategy to a set of 436 whole genome CRISPR screens, we report more than 1.5 million pairs of correlated "co-functional" genes that provide finer-scale information about cell compartments, biological pathways, and protein complexes than traditional gene sets. Lastly, we employed a gene community detection approach to implicate core genes for cancer growth and compress signal from functionally related genes in the same community into a single score. This work establishes new algorithms for probing cancer cell networks and motivates the acquisition of further CRISPR screen data across diverse genotypes and cell types to further resolve complex cellular processes

New developments in magneto-optic interferometric switching

In the next few decades, it is likely that high bandwidth wireless and optical technologies will be placed in the spotlight as the dominant avenues for communication all over the world. It is arguable that this is currently the case, and that the expectation for higher data transfer speeds, more secure and reliable transmission, and longer communication range is on an exponential rise. Thus, much effort and emphasis is being put on these technologies to advance as quickly as possible. For optical systems, the majority of research has been focused on the realization of all-optical transmission, that is, transmission such that no energy conversions (e.g. optical-electrical) take place in the transmission process. In many cases this has been achieved utilizing electro-optic (EO) and magneto-optic (MO) phenomena in special materials. Here, the use of interferometric techniques can enable optical switching and routing with the help of applied electric or magnetic fields to the special materials as light traverses through them. There are many challenges in the design of these switches. For magneto-optic interferometric devices, the magnetic field generator tends to be quite large compared to the optical transceivers deployed today. Due to their large size, current and voltage requirements tend to be excessive as well. It is important to continue to reduce the size and power requirement of these devices to ensure compatibility with current systems. In this work, new improvements to the magnetic field generators and new configurations of MO interferometric switches and routers are proposed and implemented. Additionally, studies toward a monolithically integrated MO switch are presented which include preliminary design and simulation of on-chip rib waveguides, couplers, and magnetic field generators at the micron scale

Biology in education

Not availabl

The Importance of the Inelastic and Elastic Structures of the Crust in Constraining Glacial Density, Mass Change, and Isostatic Adjustment From Geodetic Observations in Southeast Alaska

Elastic deformation of the solid Earth in response to ice mass loss offers a promising constraint on the density of glacial material lost. Further, the elastic response to modern deglaciation is important to constrain for studies of glacial isostatic adjustment to determine the mantle’s structure and rheology. Models of this elastic uplift are commonly based on the 1‐D, seismically derived global average Preliminary Reference Earth Model and typically neglect uncertainties that can arise from regional differences in elastic structure from that of the global average, lateral heterogeneities within the region, and inelastic behavior of the crust. We quantify these uncertainties using an ensemble of 1‐D local elastic structure models and empirical relations for the effects of inelasticity in the upper ∼10 km of the crust. In Southeast Alaska, modeling elastic uplift rates with local elastic structures results in up to a 20–40% difference from those modeled with the Preliminary Reference Earth Model. Although these differences are limited to regions near to ice‐covered areas, they are comparable to the differences in uplift rates expected from the loss of firn versus loss of ice. Far from ice‐covered areas, where most of the region’s GPS observations were made, these differences become insignificant and do not affect previous glacial isostatic adjustment studies in the region. The methods presented here are based on the globally available LITHO1.0 seismic model and open source software, and the approach of using an ensemble of 1‐D elastic structures can be easily adapted to other regions around the world.Key PointsElastic uplift rate uncertainty quantified using local 1‐D models has implications for glaciological studies constrained by elastic upliftIn Southeast Alaska, these uncertainties are insignificant past 1 km distance from glaciated areas and do not affect previous studies of GIAThe inelastic behavior of the upper 10 km of the crust is a significant source of uncertainty in near‐field elastic deformation estimatesPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148245/1/jgrb53217.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148245/2/jgrb53217-sup-0001-supplementary.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148245/3/jgrb53217_am.pd

ANAMMOX IN A TEMPERATE ESTUARY

PhDThe seasonal variation of anammox is yet to be comprehensively studied, unlike denitrification, the more traditional sink for fixed nitrogen. A seasonal study of anammox, denitrification and benthic oxygen consumption using the revised isotope pairing technique is presented in Chapter 2. Experimental temperature and NO3- concentration were kept constant throughout so that the capacity of the sediment for anammox could be estimated. Similar seasonal variations in the rates of anammox, denitrification and oxygen consumption suggest that anammox is controlled by the availability of organic carbon. Furthermore the effect of tidal inundation by overlying water rich in NO3- was investigated by measuring rates of anammox, denitrification and oxygen consumption at three tidal elevations throughout the year. A significant relationship between anammox and denitrification was established at each tidal elevation, which increased in strength as length of inundation decreased. To complement this seasonal study, additional experiments were undertaken, which are described in Chapter 3, to determine how anammox, denitrification and sediment metabolism responds to variations in experimental NO3- concentration and temperature. There were significant increases in rates of anammox, denitrification and sediment metabolism with temperature until 20oC when rates of anammox began to reduce. Furthermore there was significant variation in the response of all three processes to temperature in samples collected at different dates, which suggested that reduced bioavailability of organic carbon in the winter months was limiting the response to temperature. In addition to exploring how inorganic N is cycled in estuarine sediments, the ability of estuarine sediments to oxidize urea via nitrite was examined using 15N and 13C labelled substrates. Results, which are presented in Chapter 4, indicate that urea added to anaerobic sediment slurries was rapidly hydrolysed to ammonium before being oxidized via the anammox pathway.Natural Environment Research Council [grant number: NE/H525089/1 ]

Evaluation of Headgear Safety : A Comparative Study

The purpose of this study was to determine the relative safety of headgear safety straps. Samples from five different safety headgear straps simulated orthopedic and orthodontic use and data were collected from a series of pulls on an Instron machine. The straps were compared by the distance the face bow traveled before the safety mechanism released, the force built into the face bow at safety release and the force required to remove the inner bow out of the molar tube. The conclusions are as follows: (1) the distance a face bow can travel from the molar tube and still be intraoral is 24.3 mm, (2) the definition of a relatively safe headgear strap is a strap that allows the face bow to travel less than 24.3 mm, (3) the definition of an absolutely safe headgear strap is a strap that does not allow the inner bow to leave the molar tube, (4) one strap met the standard of relative safety at orthodontic and orthopedic preloads, (5) two straps qualified as relatively safe at orthopedic preloads, but did not meet the safety standard at orthodontic preloads, (6) two straps did not meet the definition of relative safety at orthodontic or orthopedic preloads, (7) no headgear strap proved to be absolutely safe, and (8) the clinical use of headgear, whether lighter or heavier forces are used, has an affect on the safety of their release mechanism

Nebraska Deer

IN COMMON with the experience of most states, Nebraska\u27s deer herds were reduced to a very low level by excessive harvests in our early history. Most American big-game animals were overharvested in the early history of this nation because of commercialization. Buffalo were killed for their hides, deer for their meat. This slaughter continued as long as the hunter (or poacher) could sell his take at a profit. Modem game management and public opinion reversed this trend. Deer are on the way back all over America, and in some states the protection-complex was so strong that deer were restored to such high population levels as to be detrimental .to the deer, their range, and the crops of the men who own that range. In Nebraska our restoration efforts have borne fruit, and we have reached that stage where adequate harvest is becoming a major factor in our deer management problems. This bulletin is intended to give the rea der essential information concerning deer, their management, and their harvest. Public understanding and active participation in the management and use of this great resource is essential. In truth, the most important factor of all in this restoration and use of a great wildlife resource, is you, Mr. Citizen. May we have your understanding and help

Turf wars: experimental tests for alternative stable states in a two-phase coastal ecosystem

Alternative stable states have long been thought to exist in natural communities, but direct evidence for their presence and for the environmental switches that cause them has been scarce. Using a combination of greenhouse and field experiments, we investigated the environmental drivers associated with two distinctive herbaceous communities in coastal ecosystems in New Zealand. In a mosaic unrelated to micro-topography, a community dominated largely by native turf species (notably Leptinella dioica, Samolus repens, and Selliera radicans) alternates with vegetation comprising exotic (i.e., nonnative) pasture species (notably Agrostis stolonifera, Holcus lanatus, Lolium perenne, and Trifolium repens). The species of these two communities differ in functional characters related to leaf longevity and growth rate, and occupy soils of differing nitrogen levels. Both spatial and environmental factors influenced the species composition locally. Reciprocal transplants of soil, with and without associated vegetation, showed that a native turf community developed when sward or soil from either community was bounded by turf, and a pasture community developed when sward or soil from either community was surrounded by pasture. In artificial mixed communities in the greenhouse, turf was able to invade the pasture community where the vegetation was clipped to simulate grazing, and also where Trifolium was removed and/or salt spray was applied. The pasture community invaded the turf where Trifolium was present or nitrogen was added. These results were supported by trends in experimentally manipulated field plots, where the amount of turf cover increased when nitrogen was kept low and when salt spray was applied, whereas pasture cover increased in the absence of salt spray. Thus, persistence of the native turf community is dependent on grazing, both directly and via its effect on keeping nitrogen levels low by excluding the exotic, nitrogen-fixing Trifolium, and by exposing the vegetation to salt spray. If any of these factors change, there could be a state change to pasture dominance that might be resistant to reversion to turf. Managing such coastal herbaceous communities therefore requires an understanding of the environmental and species characteristics that maintain alternative states