In this thesis a number of aspects on possible manipulation of Bose-Einstein condensate in trapped atomic gases is investigated. First, a model for atom optical experiments involving Bose condensates is proposed and numerical simulations are presented to illustrate its characteristics. We demonstrate ways of focusing and splitting the condensate by modifying experimentally adjustable parameters. We show that there are at least two ways of implementing atom optical elements: one may modulate the interatomic scattering length in space, or alternatively, use a sinusoidal, externally applied potential. The temporal evolution of quasiparticle excitations is studied via the Gross-Pitaevskii Equation. Nonlinear mode mixing of quasiparticles is introduced, and is observed using a quasiparticle projection method. This is used as a basis of time-dependent finite temperature simulations, which we argue to be valid under regimes of high occupation number. An illustration via a closely related evaporative cooling simulation is provided. A phenomenological damping formalism for superfluidity near the λ point is adopted to describe the damping of excitations in a Bose-Einstein condensate. An estimate for the damping parameter is found. The damping formalism as a numerical tool to calculate the ground eigenstate of the condensate is explored. A novel, experimentally realisable interferometry for Bose-Einstein condensates using near-field diffraction is proposed. The scheme is based on the phenomenon of intermode traces or quantum carpets; we demonstrate the structured spatio-temporal pattern for the dilute, atomic Bose-Einstein condensate. The pattern is found to change with temperature, which allows us to perform interferometric temperature measurements. Finally, an output coupler for Bose-Einstein Condensates based on stimulated Raman transition is investigated. The spectrum and coherence are calculated for an atomic beam slowly coupled out of a trap containing a partially condensed Bose gas at finite temperatures. A number conserving Hartree-Fock-Bogliubov formalism has been used to incorporate finite temperature effects. Various different processes are found to become dominant for a suitable choice of the coupling parameters.

This is an investigation of the British Columbia trapping industry and associated markets. A major part of the study is devoted to familiarizing the reader with the present industry. The product, trapline tenure, trappers, fur traders, earnings from trapping, marketing of the product, and administrative arrangements are described. Many problems are associated with the industry today — low incomes; raw fur prices which are declining, uncertain, and unstable; widespread ignorance of proper trapping techniques, pelt handling methods, and marketing opportunities; factor immobility; and lack of organization and contact among trappers. At the local level, there is little competition among fur buyers. Either there is only one trader in an area, or if there is more than one, they often collude. In some areas, market imperfections such as ignorance of outside markets and lack of access to capital, provide an opportunity for fur buyers to exploit the primary producers. Public administrative policies are analyzed in terms of their economic consequences, and their ability to handle the problems of trappers. Present policies lack clearly defined goals, are outdated, fail to consider the socioeconomic needs of trappers, and provide few incentives for efficiency in resource use and development. Management devices succeed in conserving the resource (once the most basic problem), but today with raw fur prices low in comparison to a decade ago, they systematically lead to an underutilization of the resource. In the absence of any organized competition for traplines, there is little assurance that the rights are possessed by the most efficient producers. The primary method of raising revenue, the collection of royalty, negates the efficiency of the management system by encouraging economizing on the harvest and failure to report all animals trapped. Traders' fees ration buying rights on the basis of differential fees. Industry structure has been stagnated by measures that prevent flexibility in the scale of trapping operations. Management lacks adequate information for informed policymaking. And non-enforcement of regulations and lack of control over Indian trapping further decreases the effectiveness of the management system. Moreover, there is no effective organization for rationalizing conflicting land-use problems. As a way of overcoming these problems and leading to a more efficient development of the fur resource, the following recommendations are made: (i) full negotiability of trapline boundaries, (ii) disposition of trapline rights through public auction, (iii) simplification but expansion of present trappers' return form to include more information, (iv) extension of licensing and questionnaire requirements to all trappers, regardless of ethnic origin, (v) enforcement of regulations, (vi) abandonment of royalties, (vii) reduction of fur-traders' fee to one nominal amount, (viii) expansion of trapper education programs, (ix) encouragement of the growth of trapping organizations, and (x) special recommendations for Indians. Data and information on which this thesis is based were obtained from: (i) the provincial Fish and Wildlife Branch and the Dominion Bureau of Statistics, (ii) personal correspondence and interviews with trappers, fur buyers, provincial fur administrators, and Indian Affairs Branch authorities, (iv) mailed questionnaires to fur traders, (v) trappers' manuals, (vi) "A Report on the B.C. Fur Resources Study" (unpublished manuscript), and (vii) fur industry studies for other provinces. A sample of income for trapping in British Columbia was derived through the use of simple mathematics, provincial average fur value statistics, and the trappers' returns. / Arts, Faculty of / Vancouver School of Economics / Graduate

Biologists often trap animals to obtain information on them. If trapping is selective toward some animals, the information may be inaccurate. Most mammalogists know or suspect that their trapping techniques (reviewed by Hayne, 1949; and Stickel, 1954) contain sources of bias. Since trapping remains the only feasible way to obtain information on many animals, researchers have tried to discover sources of sampling error and refine their techniques. They have found that one major source of difficulty may lie in the behavior of animals. Individual animals seem to respond differently to trapping, both initially and through learning (Geis, 1955; Crowcroft and Jeffers, 1961; and others). However, researchers seldom observe the behavioral responses of animals to traps. They infer information from capture data. Perhaps an empirical approach would shed more light on the relationship between behavior and trapping. The present study is such an approach. The study concerns the behavioral responses of adult Uinta ground squirrels, Citellus armatus, to trapping. I based the study on the direct observations of known individuals in a wild population. My primary objective was to learn how animals respond to a trap, to capture, and to recapture. My approach was both that of a population ecologist interested in factors affecting trapping success and that of a behaviorist interested in the effect of trapping procedures on the behavior of animals. I conducted a broad ecological and behavioral study of the population (Balph and Stokes, 1963) before beginning the research on trap response, which helped me select parameters and develop procedures. I also conducted a pilot study on deer mice, Peromyscus maniculatus, in the laboratory to test some procedures and the design of the trap-response investigation.

We present an efficient and effective method for trapping chukars (Alectoris chukar) on artificial water sources. We compared a B-trap, a prairie chicken (Tympanuchus cupido) walk-in trap, a modified quail recall trap, and a newly designed Utah walk-in-funnel trap. Our Utah funnel trap outperformed standard techniques by more than 65%, and exceeded previous published results by 35%. Use of this method allows researchers and managers the ability to capture large numbers of Chukars relatively efficiently. With appropriate modifications this design is applicable for capturing a variety of bird species using small water developments. Chukars (Alectoris chukar) have been introduced throughout the world. Limited information regarding seasonal survival, causes of mortality, and other basic life history characteristics such as movements, home range, nesting and brood ecology, are available throughout their historical and introduced range of distribution. Lack of information is surprising because chukars have been introduced throughout the world and are popular with sport hunters. Survival estimates are particularly important for understanding population fluctuations which allows for adequate management. We evaluated the relationship of fall raptor migration, peak migration, reproductive period, and year effects on survival of chukars at 5 sites in western Utah. We also evaluated the probable cause of death for chukars with transmitters attached by examining evidence at kill sites. We captured and fitted 128 chukars with two different sized radio transmitters (99 females, 21 males, 8 sexes undetermined). Survival differed among study years where survival estimates showed significant (P< 0.01) differences between estimates in 2005 (Ψ = 0.03, 95% CI = 0.01 - 0.09), compared to 2006 (Ψ = 0.26, 95% CI = 0.18 - 0.38). Estimates showed that chukars were less likely to survive (P = 0.01) during the fall peak of raptor migration in 2006 (bi-monthly Ψ = 0.86, 95% CI = 0.74 - 0.93) than (base survival) outside this migration period and during the chukar reproductive period (bi-monthly Ψ = 0.97, 95% CI = 0.95 - 0.98). We documented 95 deaths; with 45% of causes unknown, avian predation accounted for 30%, mammals killed 1%, and hunters accounted for 7.6%. Our research suggested that predation on chukars was substantial during the fall raptor migratory period.

Nanofluidic devices are structures having at least one dimension in the submicron range, which is of the same order of magnitude as the sizes of biomolecules and bioparticles such as proteins and viruses. As a result, size-selective separations are important applications for nanofluidics. Well-defined micro or nano device structures fabricated via micromachining have greatly reduced sample consumption and enabled separations in a parallel fashion, promising significant speed and resolution advantages over conventional size separation techniques, such as gel electrophoresis and size exclusion chromatography. In collaboration with others, I have developed a size separation method using nanofluidic devices consisting of an array of parallel planar nanochannels with varying heights. Separation of nanoparticles is accomplished by simply flowing a liquid suspension of the particles through the nanochannels via capillary action. When a mixture of particles arrives at an interface, where the channel steps from a deeper to a shallower segment, larger particles become trapped and smaller particles pass through, thereby achieving separation. In this dissertation, I demonstrated the successful trapping of polymer nanobeads and two types of virus capsids (30 nm hepatitis B virus capsids and 120 nm herpes simplex virus type 1 capsids) using nanochannels with two different channel height segments. Furthermore, I studied the fractionation of nanoparticles in nanochannels with three different channel height segments. The effects of surfactants and an alternating current electric field on particle distribution were investigated, both of which aided in the prevention of channel clogging. Most recently, I applied the nanosieving method for separating lipoproteins, which are important in the diagnosis of cardiovascular disease. Promising results were obtained, indicating that the major lipoprotein classes, including intermediate density lipoproteins (IDL, 23-35 nm), low-density-lipoproteins (LDL, 18-25 nm) and high-density-lipoproteins (HDL, 5-12 nm), may eventually be fractionated using three-segment nanochannels. To successfully fractionate lipoprotein mixtures, characterization of flow dynamics in three-segment nanochannels, passivation of the surface to prevent nonspecific protein adsorption, application of an electric field to help particles overcome an energy barrier, and use of multi-color fluorescent labeling to assist detection are required. I studied the channel passivation performance of polyethylene glycol (PEG) and used dual-color fluorescence detection for the separation of a binary protein mixture. Finally, I fabricated channels with monotonically changing barrier heights and demonstrated differential trapping of polymer beads. The data trend followed a slit model derived from a model developed by Giddings for size exclusion chromatography.

Despite the fact that eight cases of Lyme disease were diagnosed in San Luis Obispo County between 2005-2013, the identity of wildlife hosts serving as sources for tick infection in this region remained unidentified. The primary cause of Lyme disease in the U.S. is the spirochetal bacterium Borrelia burgdorferi sensu stricto, and this agent had not been previously isolated from the region. Borrelia bissettii, a related species that has not been implicated as a common causative agent of Lyme disease, was isolated in small rodents inhabiting coastal scrub and chaparral habitats in a previous San Luis Obispo County study. However, B. burgdorferi was not detected. In northwestern California, B. burgdorferi has been primarily associated with high populations of the tick vector Ixodes pacificus in dense woodlands or hardwood-conifer habitats, particularly in the western gray squirrel reservoir host, Sciurus griseus. My study investigated the role of S. griseus and other associated rodents as potential reservoirs for B. burgdorferi in central coastal California woodland habitats. Rodents were live-trapped at four sites in San Luis Obispo County in oak and mixed woodland. Rodent ear samples were tested for B. burgdorferi genospecies by bacterial culture and PCR. Ticks were collected from captured rodents and surrounding environments and tested by PCR for the presence of Borrelia. Of 119 captured rodents, seven were positive for Borrelia infection (5.9%) and of these, six were positive for B. burgdorferi (5.0%). There were multiple infected rodent species that included two western gray squirrels, three deer mice (Peromyscus maniculatus), and one brush mouse (P. boylii). Borrelia spp. were not detected by PCR from the 81 ticks recovered from the environment and rodents. Here, for the first time, we verify the presence of B. burgdorferi sensu stricto in San Luis Obispo county rodents. However, in contrast to previous Northern California studies, the western gray squirrel may not be the primary reservoir host for B. burgdorferi in this region. Multiple rodent species in oak woodlands may be involved in spirochete maintenance in San Luis Obispo County.

Ferroptosis is a recently characterized iron-dependent form of regulated cell death associated with the accumulation of (phospho)lipid hydroperoxides. Since its characterization, there has been a spirited debate in the literature over the origin of the lipid hydroperoxides in ferroptotic cells. Many investigators have implicated lipoxygenases (LOXs), enzymes known to catalyze the oxidation of polyunsaturated fatty acids (especially linoleate and arachidonate) to yield lipid hydroperoxides. Previous work by our group, investigated the induction and suppression of ferroptosis in human embryonic kidney (HEK-293) cells transfected to overexpress the three most widespread isoforms of LOX (5-LOX, 15-LOX-1 and p12-LOX). The results suggested that LOX catalysis is not required for ferroptosis. Our previous work did not include investigations into cells transfected to overexpress 15-LOX-2. However, a series of recent publications has since implicated the 15-LOX-2/PEPB1 complex as a key player in ferroptotic cell death. Therefore, in this work, HEK-293 cells were transfected to overexpress the 15-LOX-2 isoform, as confirmed by immunodetection, and were subject to induction and suppression of ferroptosis pharmacologically. A library of small molecules was assembled consisting of LOX inhibitors, radical-traping antioxidants (RTAs) and LOX inhibitors that display off-target RTA activity. Consistent with our previous investigations, only LOX inhibitors with radical trapping activity or iron chelators were effective at suppressing ferroptosis. Furthermore, the poor performance of 15-LOX-2 inhibitors at rescuing cells transfected to overexpress 15-LOX-2 from ferroptosis does not support the role of the 15-LOX-2/PEBP1 complex as a central mediator of ferroptotic lipid peroxidation. We also report the details of corresponding investigations in cell lines that are reported to express high levels of LOXs and that have been used to establish characteristics of ferroptosis, including HT-22 mouse hippocampal cells (15-LOX-1 and/or 15-LOX-2) and HT-1080 human fibrosarcoma cells (all LOXs). The two cellular models were also subject to cell-rescue studies with our small molecule library. Again, only LOX inhibitors that possess radical-trapping antioxidant activity or which are good iron chelators could rescue cells from ferroptosis. These results underscore our previous conclusion that although lipoxygenase activity may contribute to the pool of cellular lipid hydroperoxides, autoxidation drives ferroptotic cell death.

No description available.

No description available.

The aim of this research is to identify problematic microstructural features as hydrogen traps in linepipe steel that serve to increase the hydrogen embrittlement susceptibility. A comparison is made between the hydrogen trapping capacity and associated hydrogen embrittlement susceptibility of Ca-treated X60 grade steel skelp and X70 grade steel skelp: the latter typically being more susceptible to hydrogen-induced cracking in sour environments. Through-thickness variations in the steel skelp microstructure were characterized across multi-length scales using light optical microscopy (LOM) and scanning electron microscopy (SEM) equipped with X-ray energy dispersive spectroscopy (EDS). Key features under study include the composition, shape, and distribution of non-metallic inclusions, as well as differences in features present between the quarterline (¼ and ¾ depths) and centerline (½ depth) microstructures. The type, count, and average size of inclusions present in both steel skelp grades were analyzed using an automated SEM-EDS technique called ASPEX®. Major types of inclusions detected in both grades of steel skelp include those containing Ca, Al, Mn, Mg and Ti as major elements. Overall, the area fraction of inclusions detected in the X70 steel was larger than those detected in the X60 with the exception of Ti-containing inclusions, which had a larger area fraction within the X60 steel. Comparing the number of detected inclusions shows that there was overall slightly less Ca-containing inclusions and significantly less Ti-containing inclusions detected in the X70 steel but there was generally more Al-containing, Mg-containing, and Mn-containing inclusions than those detected in the X60 steel. Thermal desorption spectroscopy (TDS) measurements were made on samples prepared from the ¼, ½, and ¾ depths of X60 and X70 steel skelps after galvanostatic cathodic charging in an As2O3-containing solution using an applied current density of −10 mA/cm2. Hydrogen release was measured using a HYDROSEEL® probe while the sample was heated from 20°C to 650°C to detect temperature values at which hydrogen gas release peaks occurred, and thus provide information on types of reversible and/or irreversible traps present. The TDS results suggests that non-metallic inclusions indeed serve as irreversible traps along with grain boundaries and dislocations, which serve as reversible traps. Hydrogen permeation measurements were also made on samples prepared from the ¼, ½, and ¾ depths after galvanostatic cathodic charging in an As2O3-containing solution using an applied current density of −10 mA/cm2. Hydrogen gas release was measured using a HYDROSEEL® probe while the sample remained at room temperature (~20°C), providing information regarding the potency of reversible hydrogen traps when subjected to a flux of hydrogen. Only reversible traps can be detected at room temperatures due to their low binding energies. Higher temperatures are required to overcome the larger binding energies associated with irreversible traps. The hydrogen permeation results indicate no significant effect of through-thickness variations in the X60 steel, but the centreline depth of the X70 steel skelp trapped a larger quantity of hydrogen than either of the two quarterline depths, indicating the presence of a distinct problematic trap. The X70 steel skelp was also observed to trap more hydrogen than the X60 steel skelp. The observed hydrogen trapping capacity was linked to the hydrogen embrittlement susceptibility by comparing the uniaxial tensile behaviour of centreline samples with and without hydrogen charging applied as a pre-treatment step. Hydrogen charging was achieved by galvanostatic cathodic polarization at an applied current density of −10 mA/cm2 for 24 h in an NH4SCN-containing solution while simultaneously loading the samples to 85% of the yield strength using a proof ring tensile test cell. An increase in hydrogen embrittlement as a result of pre-charging was confirmed through tensile plots by comparing the area of reduction and failure strain of charged samples to uncharged samples. A decrease in both values was observed in the charged samples indicating a loss in ductility as a result of hydrogen charging. Fracture surfaces were imaged using SEM and inclusions of interest were analyzed for elemental composition using EDS. Inclusions observed along the fracture surfaces include oxysulfides of Ca and Al, oxides of Mg, Al-Ca-Si oxides, and Al2O3-containing inclusions which are likely to be heterogeneous Al-Ca-O inclusions. / Thesis / Master of Applied Science (MASc)