Attractive silences in cricket courtship song : mate choice using a short-range signal /

Matings systems using signals for sexual communication have been studied extensively and results commonly suggest that females use these signals for locating males, species-identification, and mate choice. Although numerous mating systems employ multiple signals, research has generally focused on long-range signals perhaps due to their prominence and ease of study. This study focused on the short-range acoustic courtship song of crickets. The results presented here suggest this signal is under selection by female choice. Females mated preferentially with males having shorter silences between the two types of ticks within the song. The length of these silences (Gap 1) was correlated with male condition such that males having long silences were significantly lower in mass with respect to body size when compared to males having short silences. Both Gap 1 length and male condition were significantly repeatable within males over time suggesting the possibility these traits have a genetic basis. This study is the first empirical study to test female preferences within the natural variation of the courtship song. It now appears, at least in crickets, that both the longand short-range signals of a multi-signal mating system may contribute to male mating success.

The battle over deficits : the struggle to maintain Canada's social welfare state : a thesis /

Abstract This thesis seeks to answer a number of questions concerning the deficit and debt in Canada. It focuses pri.arily on the federal level of government but with SOBe discussion of provincial governaent policy as well. In ~997, Canada's federal debt caae close ro six hundred billion dollars - $594 billion or 74.4 % of Gross Do.estic Product (GDP) to be exact. The purpose of this theses is threefold: To find out why Canada accu.ulated such a debt, to discover if there is a so-called debt crisis; and to discover if it is possible to preserve Canada's national welfare state given the financial restraints that have been adopted by both federal and provincial governments. Politicians are torn between economist' two contrasting views regarding deficits: Neo-Keynesian and neo-conservative. The neoKeynesian school focuses al1llOst exclusively on the short term stability of the economy and tends to dismiss concerns regarding the level of debt. Neo conservatives focus almost exclusively on the perceived costs of growth in the national debt and are willing to forego any stabilization benefits to ensure that the debt is controlled. These polar view do have one thing in coa.on; both confix-. that deficits influence govermaent policies. Both of these econoBic theories will have far-reaching influences on the federal gover1lJlJent's decision-making process. These economic theories will be discussed throughout this thesis.

Biotransformations of water insoluble substrates in aqueous, two-phase and encapsulated systems /

The biotransformation of water insoluble substrates by mammalian and bacterial cells has been problematic, since these whole cell reactions are primarily performed in an aqueous environment The implementation of a twophase or encapsulated system has the advantages of providing a low water system along with the physiological environment the cells require to sustain themselves. Encapsulation of mammalian cells by formation of polyamide capsules via interfacial polymerization illustrated that the cells could not survive this type of encapsulation process. Biotransformation of the steroid spironolactone [3] by human kidney carcinoma cells was performed in a substrate-encapsulated system, yielding canrenone [4] in 70% yield. Encapsulation of nitrile-metabolizing Rhodococcus rhodochrous cells using a polyamide membrane yielded leaky capsules, but biotransformation of 2-(4- chlorophenyl)-3-methylbutyronitrile (CPIN) [6] in a free cell system yielded CPIN amide [7] in 40% yield and 94% ee. A two-phase biotransformation of CPIN consisting of a 5:1 ratio of tris buffer, pH 7.2 to octane respectively, gave CPIN acid [8] in 30% yield and 97% ee. It was concluded that Rhodococcus rhodochrous ATCC 17895 contained a nonselective nitrile hydratase and a highly selective amidase enzyme.

Bird depredation of grapes in Niagara vineyards : a novel approach to identifying spatial and temporal trends /

Although local grape growers view bird depredation as a significant economic issue, the most recent research on the problem in the Niagara Peninsula is three decades old. Peer-reviewed publications on the subject are rare, and researchers have struggled to develop bird-damage assessment techniques useful for facilitating management programmes. I used a variation of Stevenson and Virgo's (1971) visual estimation procedure to quantify spatial and temporal trends in bird damage to grapes within single vineyard plots at two locations near St. Catharines, Ontario. I present a novel approach to managing the rank-data from visual estimates, which is unprecedented in its sensitivity to spatial trends in bird damage. I also review its valid use in comparative statistical analysis. Spatial trends in 3 out of 4 study plots confirmed a priori predictions about localisation in bird damage based on optimal foraging from a central location (staging area). Damage to grape clusters was: (1) greater near the edges of vineyard plots and decreased with distance towards the center, (2) greater in areas adjacent to staging areas for birds, and (3) vertically stratified, with upper-tier clusters sustaining more damage than lower-tier clusters. From a management perspective, this predictive approach provides vineyard owners with the ability to identify the portions of plots likely to be most susceptible to bird damage, and thus the opportunity to focus deterrent measures in these areas. Other management considerations at Henry of Pelham were: (1) wind damage to ice-wine Riesling and Vidal was much higher than bird damage, (2) plastic netting with narrow mesh provided more effective protection agsiinst birds than nylon netting with wider mesh, and (3) no trends in relative susceptibility of varietals by colour (red vs green) were evident.

Calculation of the magnetic field penetration depth for high-Tc cuprate superconductors based on the Interlayer Pair Tunneling model /

In this work, the magnetic field penetration depth for high-Tc cuprate superconductors is calculated using a recent Interlayer Pair Tunneling (ILPT) model proposed by Chakravarty, Sudb0, Anderson, and Strong [1] to explain high temperature superconductivity. This model involves a "hopping" of Cooper pairs between layers of the unit cell which acts to amplify the pairing mechanism within the planes themselves. Recent work has shown that this model can account reasonably well for the isotope effect and the dependence of Tc on nonmagnetic in-plane impurities [2] , as well as the Knight shift curves [3] and the presence of a magnetic peak in the neutron scattering intensity [4]. In the latter case, Yin et al. emphasize that the pair tunneling must be the dominant pairing mechanism in the high-Tc cuprates in order to capture the features found in experiments. The goal of this work is to determine whether or not the ILPT model can account for the experimental observations of the magnetic field penetration depth in YBa2Cu307_a7. Calculations are performed in the weak and strong coupling limits, and the efi"ects of both small and large strengths of interlayer pair tunneling are investigated. Furthermore, as a follow up to the penetration depth calculations, both the neutron scattering intensity and the Knight shift are calculated within the ILPT formalism. The aim is to determine if the ILPT model can yield results consistent with experiments performed for these properties. The results for all three thermodynamic properties considered are not consistent with the notion that the interlayer pair tunneling must be the dominate pairing mechanism in these high-Tc cuprate superconductors. Instead, it is found that reasonable agreement with experiments is obtained for small strengths of pair tunneling, and that large pair tunneling yields results which do not resemble those of the experiments.

Calculation of nondifferential properties for atomic ground states /

A new method for sampling the exact (within the nodal error) ground state distribution and nondiflPerential properties of multielectron systems is developed and applied to firstrow atoms. Calculated properties are the distribution moments and the electronic density at the nucleus (the 6 operator). For this purpose, new simple trial functions are developed and optimized. First, using Hydrogen as a test case, we demonstrate the accuracy of our algorithm and its sensitivity to error in the trial function. Applications to first row atoms are then described. We obtain results which are more satisfactory than the ones obtained previously using Monte Carlo methods, despite the relative crudeness of our trial functions. Also, a comparison is made with results of highly accurate post-Hartree Fock calculations, thereby illuminating the nodal error in our estimates. Taking into account the CPU time spent, our results, particularly for the 8 operator, have a relatively large variance. Several ways of improving the eflSciency together with some extensions of the algorithm are suggested.

Can poor readers visually recognize words they are unable to read? /

The ability to learn new reading vocabulary was assessed in 30 grade 3 poor readers reading approximately one to two years below grade level; the results of the assessment were compared to the performance abilities of 33 normal readers in grade 3 as obtained from an earlier study that employed the same approach and stimuli. The purpose of the study was to examine the strategies employed by poor readers in the acquisition of new reading vocabulary. Students were randomly assigned to either a treatment group (Mixed Phonics Explicit), or to a control group (Phonics Implicit). Subjects in the Mixed Phonics Explicit groups received explicit letter/sound correspondence training. Subjects in the Phonics Implicit group were asked to re-read the presented pseudo-words, receiving corrective feedback when necessary. The stimuli on which the subjects were trained involved a list of six pseudo-words presented in sentences as surnames. The training involved a teaching and test format on each trial for a total of six trials or until criterion had been reached. The results suggested that both normal and poor readers engage in visual learning and verbal coding when acquiring new reading vocabulary. However, poor readers appear to engage in less verbal coding than normal readers. Between group comparisons showed no difference between poor and normal readers in trials and errors to criterion in the visual recognition memory measure. However, normal readers performed significantly better in reading their visual recognition choices.

Cardiovascular health risk profiling of Niagara Region grade 9 students : implications for elementary curriculum /

The purpose of this study was to determine if Ontario's health and physical education curriculum contributes sufficiently to ensure the health of our children and young adults. To determine the curriculum effect, the health risk profile of Niagara Region's grade 9 students was compared to Canada's adolescent population. All subjects completed a "Heart Health Lifestyle" survey and were measured for height, weight, percent body fat, blood pressure, and total cholesterol and performed the 20-metre shuttle run test as part of their physical and health education classes. The Niagara Region grade 9 population had a healthy risk profile. Aerobic power was inversely related, and cholesterol levels were positively associated to body mass index and percent body fat in the whole group analysis. These results indicate that physical education can offer unique and essential aspects allowing individuals a means to learn and control body movements and keep physically fit while providing protection against modern disease. Ontario's health and physical education curriculum does contribute to the health of our children and adolescents; however, there is a need to implement a stronger mandate for daily vigorous physical activity.

The challenges and successful strategies of secondary school administrators /

This study presents information gathered during personal interviews in the area of challenges that administrators have faced in their careers, and the strategies they have found to be successful in meeting those challenges. This research is a qualitative study, using an inductive approach. Five participants were chosen, based on convenience sampling, with semi-structured interviews that were audio recorded. The theoretical research found that school violence and stafS'school morale were key challenges facing administrators, with a variety of approaches suggested to foster success in meeting those challenges. Some of these approaches included knowledge, team work, an ethic of care, and having a school vision. From the interviews it became clear that the challenges administrators faced included those posed by students, including disciplinary issues, those posed by adults and those posed by government changes in education. In regards to strategies for success, the interviews revealed three key concepts that were emphasized as vital. These were the assets of craft knowledge (experience), collegiality, and the use of other professional resources and educators.

Changing roles of nurse educators employed in acute and chronic care settings : the impact of professional and statutory mandates in Ontario at four sites of one hospital corporation /

The role of the hospital-employed nurse educator is evolving. Factors influencing this change include the introduction of standards for nurse educators by the College of Nurses of Ontario (CNO), a change in the way nurses are educated, the emergence of nursing as a profession, and hospital restructuring as a result of budgetary constraints. Two of these influencing factors: the introduction of the updated Standards of Practice for Registered Nurses and Registered Practical Nurses (1996) and hospital restructuring occurred over the last 7 years at several hospitals in southern Ontario. Current literature as well as the Standards of Practice (1996) were utilized to examine the current roles and responsibilities of nurse educators and subsequently develop a questionnaire to study the impact of these influencing factors on the role of the nurse educator. This questionnaire was piloted and revised before its distribution at 4 hospitals in southern Ontario. Twenty-five of the 41 surveys (61%) distributed were returned for analysis. The data reflected that the Standards of Practice had a positive influence on the role of the nurse educator, while hospital restructuring had a negative impact. In addition, many of the roles and responsibilities identified in the literature were indeed part of the current role of nurse educators, as well as several responsibilities not captured in the literature. The predictions for the future of this role in its current state were not positive given the financial status of the health care system as well as the lack of clarity for the role and the current level ofjob satisfaction among practicing nurse educators. However, a list of recommendations were generated which, if implemented, could add clarity to the role and improve job satisfaction. This could enhance the retention of current nurse educators and the possibility of recruiting competent nurse educators to the role in the future.

Characterization and protein fingerprinting of Botrytis cinerea isolates /

Botrytis cinerea isolates collected from Niagara region were treated with different concentrations of the fiingicide, iprodione to test their sensitivity to this fungicide. These Botrytis cinerea isolates were divided into two groups according to their sensitivity to iprodione. Those isolates whose growth was inhibited by iprodione at concentrations < 2|i,g/nil were classified as sensitive isolates. Isolates that were able to show considerable growth at 2|j,g/ml iprodione were classified as resistant isolates. Resistant and sensitive isolates were compared for their morphological and growth characteristics, conidial germination, virulence on grape berries and protein banding profiles. The fungicide iprodione at a concentration of 2|xg/nil inhibited mycelial growth, sporulation and conidial germination of sensitive isolates but not those of resistant isolates. The inhibitory effect of the fungicide was greater on mycelial growth than on conidia germination of the sensitive isolates. Sensitive isolates produced no sclerotia whereas resistant isolates produced large number of sclerotia. The fungicide iprodione affected sclerotial production in the resistant isolates. The number of sclerotia was decreased by the increase of iprodione in the medium. Sporulation of resistant isolates was improved significantly in the presence of iprodione. The resistant isolates were as virulent as the sensitive isolates on grape berries. The sensitive and resistant isolates showed similar protein banding profiles in the absence of iprodione in polyacrylamide gel electrophoresis studies. Similar protein profiles were also observed when these isolates were grown in the presence of low iprodione concentration (0.5|ig/nil). However, in the presence of concentration (0.5|ig/nil). However, in the presence of iprodione at concentration of 5|Xg/nil, one protein band with approximate molecular weight of 83 KDa was present in the growing resistant isolates (and the controls) but was missing in the inhibited sensitive isolates.

The characterization of new benzimidazole fungicides /

Extensive studies have been initiated to generate enough data to register the methyl homologue (MBC-MIC, see List of Abbreviations, page 14) of benomyl (MBC-BIC) as a commercial product through a joint effort between the federal government and Canadian industry. The objective of this study, as part of the whole project, was to generate fundamental data on the physical properties of the series of benomyl homologues (MBC-MIC, MBC-EIC, MBC-PIC and MBC-BIC). These data include the half lives of these compounds in water at the pH range from 2 to 12; they ranged from 0.7 to 10. 1 hours. Standard solutions of these compounds in concentrated acid were found to be stable for at least two weeks, and in the case of MBC-MIC it was stable at least 1 month. Another major goal of this study was to determine the solubility of each compound in water at different pHs in the range of 1 to 12. The solubility of the compounds ranged from 0.6 jig/mL to 396 fig/mL. In addition, it was possible to prepare stable stock solutions at concentrations > 1 000 |ig/mL in concentrated nitric acid. Several aspects of analytical methods have been improved to accurately assess the solubility and rate of degradation of benomyl and its homologues in alkaline conditions. The determination of melting points was attempted but all compounds decomposed before melting.To complement the studies of the benomyl homologue series attempts were made to explore the presence of any relationships between the structures of the compounds and their properties. Although there were some exceptions, the compound's solubility decreased and half life increased as the molecular size increased from the methyl to the butyl analogue.

Charting the territory : how female artist/teachers balance their artistic practice with their institutional responsibilities as teachers /

This r\.~et.lrch examined ho\\' ~ight \\'omen artists \\'ho t~ach at the uni versity and college level, balance thcir artistic practic~ and their institu tional responsibilities as tcachers. This thesis reprt.~ents the culmination of \\'ork for my second graduate degree. For my first degrCt! on th~ grad uat~ level, I concentratoo on d~veloping my artistic practice. This ~Iaster's Degree in Education is no k~ important to m~. In pursuing studies in the field of education I \\'anted to understand my rol~ as both an educator and an artist and in the process I uncovered the interplay of race, class, and gender at \\'ork in th~ classroom. Coming from a \\'orking-class, immigrant background \\'here higher education \vas vie\\'cd as a stepping stone that \"ould enable my siblings and me a greater spectrum of opportunities, I \\'as at last able to understand my o\\'n educational experiences, more clearly. I discovered ho\\' d\.~ply I internalized the racism, sexism and class discrimination, I submitted to in my history as a student. Becoming a\\'are about the social forc\.~ at "'ork \\'ithin my day to day life has provided me \\'ith instruments \\'hich I can usc to examine and respond to these inequities as I confront them in th~ future. This \,'ork exists as a serk'S of responses and further av~nues for investigation on some themes I first began to explor~, albeit very tentati\'~ly, during my first incarnation as a graduate student and so though the h\'o bound volum~s rna-\' one da.v sit si.d~ b\' s id~ on the bookshelf, th~\-' exist in the context of my life as a set of brackets surrounding a series of qUl'Stions about being a \\'Onlan, a teachcr and an artist.

Childlessness in a child-centered environment : the experiences of voluntarily childless female teachers /

In the literature on voluntary childlessness there is a lack of research on the types of occupations held by women who choose not to mother and how their fertility choice influences their occupational experiences. At the same time, the experience ofwomen with regard to the childfree choice has not been adequately addressed in contemporary feminist literature. In the field of education, much has been written about the association between mothering and teaching. Thus, childfree teachers become particularly interesting since they made seemingly paradoxical choices in that they chose not to bear and rear children yet they chose an occupation in which they are surrounded by and responsible for the daily care of many children. To gain an understanding of the work-related experiences of childfree women, in-depth interviews were conducted with 7 voluntarily childless female elementary school teachers from Southern Ontario. In addition, a focus group interview in which 3 of the 7 childfree teachers participated was conducted. Findings revealed that these women's "choice" to be childless was the result of complex circumstances and multiple motivations. Also, despite their decision to forgo the traditional female role of mother, these women held surprisingly conventional beliefs with regard to family and gender roles. In addition, these childfree women at times identified themselves as mother-like when teaching, yet at other times distanced themselves as teachers from mothers. Finally, results showed that these women experienced both direct and indirect pronatalist pressures outside as well as inside the workplace as a result of their childfree status.

Cloning, sequencing and characterization of a chitin synthase gene fragment from the fungus Phascolomyces articulosus /

Phascolomyces articulosus genomic DNA was isolated from 48 h old hyphae and was used for amplification of a chitin synthase fragment by the polymerase chain reaction method. The primers used in the amplification corresponded to two widely conserved amino acid regions found in chitin synthases of many fimgi. Amphfication resulted in four bands (820, 900, 1000 and 1500 bp, approximately) as visualized in a 1.2% agarose gel. The lowest band (820 bp) was selected as a candidate for chitin synthase because most amplified regions from other fimgi so far exhibited similar sizes (600-750 bp). The selected fragment was extracted from the gel and cloned in the Hinc n site of pUC19. The derived plasmid and insert were designated ^\5C\9'PaCHS and PaCHS respectively. The plasmid pUC19-PaC/fS was digested by several restriction enzymes and was found to contain BamHl and HincU sites. Sequencing of PaCHS revealed two intron sequences and a total open reading frame of 200 amino acids. The derived polypeptide was compared with other related sequences from the EMBL database (Heidelberg, Germany) and was matched to 36 other fiilly or partially sequenced fimgal chitin synthase genes. The closest resemblance was with two genes (74.5% and 73.1% identity) from Rhizopus oligosporus. Southern hybridization with the cloned fragment as a probe to the PCR reaction showed a strong signal at the fragment selected for cloning and weaker signals at the other two fragments. Southern hybridization with partially digested Phascolomyces articulosus genomic DNA showed a single band. The amino acid sequence was compared with sequences from other chitin synthase gene classes using the CLUSTALW program. The chitin synthase fragment from Phascolomyces articulosus was initially grouped in class n along with chitin synthase fragments from Rhizopus oligosporus and Phycomyces blakesleeanus which also belong to the same class, Zygomycetes. Bootstrap analysis using the neighbor-joining method available by CLUSTALW verified such classification. Comparison of PaCHS revealed conservation of intron positions that are characteristic of chitin synthase gene fragments of zygomycetous fungi.