Specific heat of UPdâ Siâ

The specific heat of single-crystal U Pd2 Si2 has been studied using both the step heating and continious heating methods for the temperature range 2 to 250 K. Successive phase transitions at Tl = 136I< and T2 = 108I< are reported, which are consistent with current publications. The transition at 40K, which was previously reported, has not been detected. Recent published elastic neutron scattering data, magnetic susceptibility and resistivity results suggest that U Pd2 Si2 may be a heavy fermion compound, however, the electronic specific heat coefficient I (= 18.97 ;~), obtained from the specific heat Cv measurements, is smaller than that of the conventional heavy fermion system. The Debye temperature of U Pd2Si2 is found to be 116.55K. The possibility is discussed that the maximum in CIT in the low-temperature range 2 to 4K corresponds to Schottky anomaly induced by localized magnetic impurities .

Spelling performance of third grade students : a comparison of whole-language-plus-strategy instruction, strategy instruction only, and the whole language approach

This study investigated three methods for teaching children how to spell. Third grade students were divided into three conditions for a one-week training period consisting of 15- to 20-minute lessons. One of the two experimental conditions used a whole language approach along with explicit strategy instruction. The second condition used strategy instruction within a traditional setting. The control used strictly a whole language approach to le~ing hO\\l to spell. The spelling perfonnance of all three conditions improved after the one-week training period. However, students in the strategy instruction groups did significantly better on the study "'7ords than the whole language only group. The students in whole-Ianguage-plusstrateg)! instruction outperformed both other groups. Significantly better spelling perfonnance was observed even at the nine-week posttest. This study frrst supported the hypothesis that children can make significantly greater improven1ents in their spelling when explicitly taught how to use spelling strategies. Secondl)', this study indicated that whole language provided a relevant context for the study words, clearly giving the students in the whole-Ianguage-plus-strategy condition an additional advantage.

Sperm utilization patterns in Gryllus integer (orthoptera: gryllidae

Sperm competition is the competition for fertilizations between ejaculates, within a female, following multiple mating. There are four sperm utilization or precedence patterns: first male precedence, where the first male to mate fertilizes most of the eggs laid by a female; last male precedence, where the last male to mate fertilizes most of the eggs laid by a female; "all-or-none" pattern, where sperm from either male fertilizes all the eggs laid by a female but which male's sperm that is used is random; or sperm mixing, where sperm from each male is used equally in fertilizing eggs laid by a female. Intermediate utilization patterns are also possible. Sperm competition occurs in a wide variety of insect species as well as other animals. This study was undertaken to study sperm competition in the field cricket, Gryllus integer. Four experiments were conducted: a radiation and sterilization experiment, a diapause experiment, and 2 competition experiments. It was found that 7,000 rad of gamma radiation sterilized adult ~ integer males. There was no diapause in the laboratory in ~ integer eggs. In the first competition experiment, three groups of females were used: females mated with a normal male, then with a second normal male (NN group); females mated with a normal male, and then with a sterile male (NR group); and females mated with a sterile male, and then with a normal male (RN group). The results obtained from this experiment showed that the mean proportion of eggs hatched was significantly different between 3 groups of females, with the proportion hatched much greater in the NN group than in either the NR or RN groups. The pattern for the proportion of eggs hatched following a double mating most closely resembled a pattern expected if sperm mixing is occurring. Results obtained in the replicate competition experiment showed that the mean proportion of eggs hatched for the females in the NR group was significantly lower than the proportion hatched in the other two groups. This also supports a model of sperm mixing as a precedence pattern. Values calculated following Boorman and Parker (1976), for the proportion of eggs fertilized by the second male to mate following a double mating, were 0.57 in competition experiment 1 and 0.62 in the replicate. These values indicate that sperm mixing occurs in~ integer.

Stolen past: Shattered futures, aboriginal justice in Canada

It is acknowledged that Canada's criminal justice system has some major flaws, particularly with respect to its application to various ethnic subgroups. Aboriginal Canadians are one subgroup particularly sensitive to the problems in the system as is reflected by their disproportionately high rates of criminality and incarceration. Over the past 50 years many programs have been developed and recommendations have been made to alleviate the tensions Aboriginals find within the system. However, the situation today is essentially the same. Aboriginals are still overrepresented within the system and solutions that have been brought forward have had little success in stemming their flow into the system. Blame for Aboriginal mistreatment in the system has been placed at all levels from line police officers to high-level officials and politicians and attempts to resolve problems continue as an on going process. However, many of the recommendations and reforms have revolved around culture conflict. Although this thesis recognizes the importance of culture conflict in the overrepresentation of Aboriginals within the Canadian criminal justice system, it has also recognized that culture conflict alone is not responsible for all the flaws within the system as it pertains to Aboriginals. This thesis is of the opinion that in order for reforms to the criminal justice system to be successful, the context in which the system is operating must also be considered. Variables such as geographic isolation, economic disparity and social/political stability are viewed as operating in conjunction with culture, ultimately influencing Aboriginal treatment within the system. The conclusions drawn from this study confirm that when these factors operate together, the overrepresentation of Aboriginals within the Canadian criminal justice system is inevitable. Thus all three variables, culture conflict (social/political stability being part), geographic isolation and economic disparity must be address within the system if any significant changes in the crime rates or incarceration rates of Aboriginals is to be expected. In addition, primary research indicated the influence of cooperation as a factor in moderating the effects of criminality; not just cooperation among Aboriginals and non-Aboriginals, but also cooperation among differing Aboriginal communities. It was argued that when all these issues are addressed, Aboriginal peoples in Canada will have the strength to repair their shattered futures.

Strong hydrogen bonding in organic synthesis

The preparation of phenacyl and para-phenylphenacyl esters, the reactions of carboxylic acids, phenols, 2-nitropropane and alcohols with alkyl halides in the presence of fluoride anion are described. The reactions are thought to be accelerated by the formation of hydrogen bonds between the fluoride anion and the organic electron acceptor. The fluoride ,carboxylic acids, fluoride-phenols and fluoride-2-nitropropane are better reaction systems than the fluoride-alcohol. The source of the fluoride anion and the choice of solvents are also discussed.

Structural effects of neutral lipids on the divalent cation-induced interactions of phosphatidylserine - containing bilayers

As Ca2+ and phosphatidylserine (PS) are known to induce the adhesion of bilayer vesicles and form collapsed multibilayer structures in vitro, it was the aim of this study to examine how that interaction and the resultant structures might be modified by neutral lipid species. X-ray diffraction data from multilamellar systems suggest that phosphatidylcholine (PC) and diacylglycerol (DG) might be in the collapsed phase up to a concentration of -30 mole % and that above this concentration these neutral lipids may modify Ca2+-induced bilayer interactions. Using large unilamellar vesicles and long incubations in excess Ca2+ to ensure equilibration, similar preliminary results were again obtained with PC, and also with phosphatidylethanolamine (PE). A combination of X-ray diffraction, thin-layer chromatography, density gradient centrifugation and freeze-fracture electron microscopy, used in conjunction with an osmotic stress technique, showed that (i) -30 mole % PC can be accomodated in the Ca(DOPS)2 phase; and (ii) higher PC levels modify Ca2+-induced bilayer interactions resulting in single lamellar phases of larger dimension and reduced tendency for REV collapse. Importantly, the data suggest that PC is dehydrated during the rapid collapse process leading. to Ca(DOPS)2 formation and exists with this dehydrated phase. Similar results were obtained using PS isolated from bovine brain. Preliminary studies using two different phosphatidylethanolamine (PE) species indicated accomodation by Ca(DOPS)2 of -25-30 mole 0/0 PE and bulk phase separation, of species favouring a non-bilayer phase, at higher levels. Significantly, all PS/PE vesicles appear to undergo a complete Ca2+-induced collapse, even with contents of up to 90 mole % PE. These data suggest that PE may have an important role in fusion mechanisms in vivo. In sum the data lend both structural and stoichiometric evidence for th~ existence of laterally segregated neutral lipid molecules within the same bilayers as PS domains exposed to Ca2+.

Student perceptions of the writing process

Based on the critical research paradigm and using a mix of methodologies, this study examined student perceptions of the process approach used to teach writing. A class of 19 ESL students in an academic writing class at a small university paliicipated in the study. As collaborators in the study, they assessed their personality types using the PET Type Check (Crantoll & Knoop, 1995) and tlleir learning styles using Kolb'sLearning Styles Inventory (1976). Interviews, classroom observations, and journals provided a data base for case studies llilQ teacher reflection. Results indicated that students perceived the prewriting step of brainstonning and peer review as most useful. Student perceptions of the tasks and course and implications for theory and practice are examined.

Students' knowledge about tobacco one year after receiving the PAL smoking prevention program

A review of literature revealed that the control of cigarette smoking could do more to improve health than any other single action in the field of preventive medicine. In Ontario, since 1989, both Public Health Units and Boards ofEducations have been mandated to provide educational studies related to tobacco use prevention. Even given this fact, there has been an increase in smoking behaviQurs at an earlier age and in females in particular. Smoking prevention progralns must use the most effective means to assist students to obtain the knowledge and skills required to remain or becom'e nonsmokers. In the Niagara Region, PAL smoking prevention programs are offered in some, but not all, schools. As a form of program evaluation, this research sought to determine if students who had PAL could answer correctly a greater number of smoking-related questions than students who did not have this program. Findings reported that students who had PAL in Grade 6 were able to correctly answer more knowledge-based questions (at a statistically significant level), could provide ways to refuse cigarettes at a greater rate, and were able to provide more reasons for remaining nonsmokers. Students who had smoking prevention programming re,ported smoking behavio'urs at a lower rate than those who did not receive this type of program.

Studies in the synthesis of 4, 5-disubu/stituted phenanthrenes /|nK. Ramakrishnan. -- 260 St. Catharines, Ont. : [s. n.],

The work described in t his thesis was initiated with the intention of exploring new routes for the synthesis of certain 4, 5-disubstituted phenanthrenes. A series of reactions have been investigated in detail and several 4, 5-disubstituted phenanthrenes have been prepared. Some of the methods employed were novel and the yields of products were comparable or even better than the existing routes . A major observation made during the course of this work was the stability of the seven-membered ring system bridging the 4 and 5 positions of the phenanthrene nucleus . It has been found t hat the unbridged structures are not preferred if the compound is capable of isomerising to a bridged form . We have explained this phenomenon in t erms of the stereochemistry of t he 4 and 5 positions of the phenanthrene nucleus as well as the geometry of the bridge . Low temperature NMR studies have been carried out to investigate the conformations of the benzylic hydrogens of some of the 4,5-bridged compounds. However, the results were not conclusive as more than one reason could be attributed t o the observations .