23 resultados para flexibility
em Brock University, Canada
Resumo:
All-electron partitioning of wave functions into products ^core^vai of core and valence parts in orbital space results in the loss of core-valence antisymmetry, uncorrelation of motion of core and valence electrons, and core-valence overlap. These effects are studied with the variational Monte Carlo method using appropriately designed wave functions for the first-row atoms and positive ions. It is shown that the loss of antisymmetry with respect to interchange of core and valence electrons is a dominant effect which increases rapidly through the row, while the effect of core-valence uncorrelation is generally smaller. Orthogonality of the core and valence parts partially substitutes the exclusion principle and is absolutely necessary for meaningful calculations with partitioned wave functions. Core-valence overlap may lead to nonsensical values of the total energy. It has been found that even relatively crude core-valence partitioned wave functions generally can estimate ionization potentials with better accuracy than that of the traditional, non-partitioned ones, provided that they achieve maximum separation (independence) of core and valence shells accompanied by high internal flexibility of ^core and Wvai- Our best core-valence partitioned wave function of that kind estimates the IP's with an accuracy comparable to the most accurate theoretical determinations in the literature.
Resumo:
The purpose of this qualitative study was to investigate the application of Cognitive Coaching as a school-based professional development program to improve instructional thought and decision making as well as to enhance staff perceptions, coUegiality and school culture. This topic emerged from personal and professional issues related to the role ofthe reflective practitioner in improving the quality of education, yet cognizant of the fact that little professional development was available to train teachers to become reflective. This case study, positioned within the interpretive sciences, focused on three teachers and how their experiences with cognitive coaching affected their teaching practices. Their knowledge, understanding and use of the four stages of instructional thought (preactive, interactive, reflective and projective) were tested before and at the end of eight coaching cycles, and again after two months to determine whether they had continued to use the reflective process. They were also assessed on whether their attitude towards peer coaching had changed, whether their feelings about teaching had become more positive and whether their professional dialogue had increased. Three methods of data collection were selected to assess growth: interviews, observations and joumaling. Analysis primarily consisted of coding and organizing data according to emerging themes. Although the professed aim of cognitive coaching was to teach the process in order that the teachers would become self-analytical and self-modifying, this study found that the value of the coaching, after trust had been established in both the coach and the process, was in the dialoguing and the time set aside to do it. Once the coaching stopped providing the time to dialogue, to examine one's meanings and beliefs, so did the critical self-reflection. As a result ofthe cognitive coaching experience though, all participants grew in their feelings of efficacy, craftsmanship, flexibility, consciousness and interdependence. The actual and potential significance ofthis study was discussed according to implications for teacher supervision, professional development, school culture, further areas of research and to my personal growth and development.
Resumo:
The kinetic study of the coupled enzymatic reaction involving monomeric yeast hexokinase PII (HK) and yeast glucose-6-phosphate dehydrogenase (G-6-PDH) yields a Michaelis constant of 0.15 ± 0.01 mM for D-glucose. At pH 8.7 HK is present in monomeric form. The addition of polyethylene glycol (PEG), to the reaction mixture increased the affinity of HK for glucose, independent ofMW of the PEG from 2000 to 10000. The osmotic stress exerted by PEG can be used to measure the change in number of water molecules that accompany enzyme conformational changes (Rand, et al., 1993). Results indicate that the G-6-PDH is not osmotically sensitive and thus, the change in the number of PEG-inaccessible water molecules (ANw) measured in the coupled reaction is only the difference between the glucose-bound and glucosefree conformations of HK. ANw ~ 450 with PEGs of MW > 2000 under conditions for both binding (Reid and Rand, 1997) and kinetic assays. The contribution water may play in the binding of ATP (Km = 0.24 + 0.02 mM) has also been examined. It was found that in this case ANw = (for osmotic pressures < 2.8x10* dynes/cm^), suggesting no additional numbers of waters are displaced when ATP binds to HK. Osmotic pressure experiments were also performed with dimeric HK. It was determined that both the monomeric and dimeric forms of HK give the same ANw under low pressures. If this large ANw is due to conformational flexibility, it would appear that the flexibility is not reduced upon dimerization ofthe enzyme.
Resumo:
In the work reported here, optically clear, ultrathin TEOS derived sol-gel slides which were suitable for studies of tryptophan (Trp) fluorescence from entrapped proteins were prepared by the sol-gel technique and characterized. The monitoring of intrinsic protein fluorescence provided information about the structure and environment of the entrapped protein, and about the kinetics of the interaction between the entrapped protein and extemal reagents. Initial studies concentrated on the single Trp protein monellin which was entrapped into the sol-gel matrices. Two types of sol-gel slides, termed "wet aged", in which the gels were aged in buffer and "dry-aged", in which the gels were aged in air , were studied in order to compare the effect of the sol-gel matrix on the structure of the protein at different aging stages. Fluorescence results suggested that the mobility of solvent inside the slides was substantially reduced. The interaction of the entrapped protein with both neutral and charged species was examined and indicated response times on the order of minutes. In the case of the neutral species the kinetics were diffusion limited in solution, but were best described by a sum of first order rate constants when the reactions occurred in the glass matrix. For charged species, interactions between the analytes and the negatively charged glass matrix caused the reaction kinetics to become complex, with the overall reaction rate depending on both the type of aging and the charge on the analyte. The stability and conformational flexibility of the entrapped monellin were also studied. These studies indicated that the encapsulation of monellin into dry-aged monoliths caused the thermal unfolding transition to broaden and shift upward by 14°C, and causedthe long-term stability to improve by 12-fold (compared to solution). Chemical stability studies also showed a broader transition for the unfolding of the protein in dry-aged monoliths, and suggested that the protein was present in a distribution of environments. Results indicated that the entrapped proteins had a smaller range of conformational motions compared to proteins in solution, and that entrapped proteins were not able to unfold completely. The restriction of conformational motion, along with the increased structural order of the internal environment of the gels, likely resulted in the improvements in themial and long-term stability that were observed. A second protein which was also studied in this work is the metal binding protein rat oncomodulin. Initially, the unfolding behavior of this protein in aqueous solution was examined. Several single tryptophan mutants of the metal-binding protein rat oncomodulin (OM) were examined; F102W, Y57W, Y65W and the engineered protein CDOM33 which had all 12 residues of the CD loop replaced with a higher affinity binding loop. Both the thermal and the chemical stability were improved upon binding of metal ions with the order apo < Ca^^ < Tb^"^. During thermal denaturation, the transition midpoints (Tun) of Y65W appeared to be the lowest, followed by Y57W and F102W. The placement of the Trp residue in the F-helix in F102W apparently made the protein slightly more thermostable, although the fluorescence response was readily affected by chemical denaturants, which probably acted through the disruption of hydrogen bonds at the Cterminal end of the F-helix. Under both thermal and chemical denaturation, the engineered protein showed the highest stability. This indicated that increasing the number of metal ligating oxygens in the binding site, either by using a metal ion with a higher coordinatenumber (i.e. Tb^*) which binds more carboxylate ligands, or by providing more ligating groups, as in the CDOM33 replacement, produces notable improvements in protein stability. Y57W and CE)OM33 OM were chosen for further studies when encapsulated into sol-gel derived matrices. The kinetics of interaction of terbium with the entrapped proteins, the ability of the entrapped protein to binding terbium, as well as thermal stability of these two entrapped protein were compared with different levels of Ca^"*^ present in the matrix and in solution. Results suggested that for both of the proteins, the response time and the ability to bind terbium could be adjusted by adding excess calcium to the matrix before gelation. However, the less stable protein Y57W only retained at most 45% of its binding ability in solution while the more stable protein CDOM33 was able to retain 100% binding ability. Themially induced denaturation also suggested that CDOM33 showed similar stability to the protein in solution while Y57W was destabilized. All these results suggested that "hard" proteins (i.e. very stable) can easily survive the sol-gel encapsulation process, but "soft" proteins with lower thermodynamic stability may not be able to withstand the sol-gel process. However, it is possible to control many parameters in order to successfully entrap biological molecules into the sol-gel matrices with maxunum retention of activity.
Resumo:
Over the past several decades, many theories have been advanced as to why efforts to reform the public service have met with only limited success. Clearly, the role of leadership with respect to reform must be examined, since successful organizational leaders should be extremely accomplished in the promotion and protection of the values that underlie decision-making. The issue of effective leadership is particularly significant for the future of the public service of Canada. Large numbers of public servants in the executive ranks are due to retire within the next five years. Given their central role, it is vital that there be enough dedicated and committed public servants to staff future vacancies. It is also essential that future public service leaders possess the competencies and values associated with a world-class public service and, a new type of public organization. Related to this point is the importance of people-management skills. People management in the public service is an issue that has historically faced - and will continue to face - major challenges with respect to recruiting and retaining the leaders it requires for its continued success. It is imperative that the public service not only be revitalized and be seen as an employer of choice, but also that the process by which it accomplishes this goal - the practice of human resource management - be modernized. To achieve the flexibility needed to remain effective, the public service requires the kind ofleadership that supports new public service values such as innovation and which emphasizes a "people- first" approach. This thesis examines the kind of public service leadership needed to modernize the human resource management regime in the federal public service. A historical examination of public service values is presented to help determine the values that are important for public service leaders with respect to modernizing human resource management. Since replenishing the 2 ranks of public service leaders is crucial to ensure the quality of service to Canadians, leadership that supports career planning will be a major focus of this paper. In addition, this thesis demonstrates that while traditional public service values continue to endure, innovative leaders must effectively reconcile new public service values with traditional values in order to increase the possibilities for successful reform as well as achieve business objectives. Much of the thesis is devoted to explaining the crucial role of post-bureaucratic leadership to successful reform. One of the major findings of the thesis is that leaders who demonstrate a blending of new public service values and traditional values are critical to creating effective employment relationships, which are key to modernizing human resource management in the federal public service. It will be apparent that public service leaders must ensure that an appropriate accountability framework is in place before embarking on reform. However, leaders who support new public service values such as innovation and empowerment and who emphasize the importance of people are essential to successful reform.
Resumo:
This research responds to a pervasive call for our educational institutions to provide students with literacy skills, and teachers with the instructional supports necessary to facilitate this skill acquisition. Questions were posed to gain information concerning the efficacy ofteaching literacy strategies to students with learning difficulties, the impact of this training on their volunteer tutors, and the influence of this experience on these tutors' ensuing instructional practice as teacher candidates in a preservice education program. Study #1 compared a nontreatment group of students with literacy difficulties who participated in the program and found that program participants were superior at reading letter patterns and at comprehending the elements of story grammar. Concurrently, the second study explored the experiences of 19 volunteer tutors and uncovered that they acquired instructional skills as they established a knowledge base in teaching reading and writing, and they affirmed personal goals to become future teachers. Study #3 tracked 6 volunteer tutors into their pre-service year and identified their constructions, and beliefs about literacy instruction. These teacher candidates discussed how they had intended to teach reading and writing strategies based on their position that effective teaching ofthese skills in the primary grades is integral to academic success. The teacher candidates emphasized the need to build rapport with students, and the need to exercise flexibility in lesson plan delivery while including activities to meet emotional and developmental requirements of students. The teacher candidates entered their pre-service education with an initial cognition set based on the limited teaching context of tutoring. This foundational ii perception represented their prior knowledge of literacy instruction, a perception that appeared untenable once they were immersed in a regular instructional setting. This disparity provoked some of the teacher candidates to denounce their teacher mentors for not consistently employing literacy strategies and individualized instruction. This critical perspective could have been a demonstration of cognitive dissonance. In the end, when the teacher candidates began to look toward the future and how they would manage the demands of an inclusive classroom, they recognized the differences in the contexts. With an appreciation for the need for balance between prior and present knowledge, the teacher candidates remained committed to implementing their tutoring strategies in future teaching positions. This document highlights the need for teacher candidates with instructional experience prior to teacher education, to engage in cognitive negotiations to assimilate newly acquired pedagogies into existing pedagogies.
Resumo:
In studies of cognitive processing, the allocation of attention has been consistently linked to subtle, phasic adjustments in autonomic control. Both autonomic control of heart rate and control of the allocation of attention are known to decline with age. It is not known, however, whether characteristic individual differences in autonomic control and the ability to control attention are closely linked. To test this, a measure of parasympathetic function, vagal tone (VT) was computed from cardiac recordings from older and younger adults taken before and during performance of two attentiondemanding tasks - the Eriksen visual flanker task and the source memory task. Both tasks elicited event-related potentials (ERPs) that accompany errors, i.e., error-related negativities (ERNs) and error positivities (Pe's). The ERN is a negative deflection in the ERP signal, time-locked to responses made on incorrect trials, likely generated in the anterior cingulate. It is followed immediately by the Pe, a broad, positive deflection which may reflect conscious awareness of having committed an error. Age-attenuation ofERN amplitude has previously been found in paradigms with simple stimulus-response mappings, such as the flanker task, but has rarely been examined in more complex, conceptual tasks. Until now, there have been no reports of its being investigated in a source monitoring task. Age-attenuation of the ERN component was observed in both tasks. Results also indicated that the ERNs generated in these two tasks were generally comparable for young adults. For older adults, however, the ERN from the source monitoring task was not only shallower, but incorporated more frontal processing, apparently reflecting task demands. The error positivities elicited by 3 the two tasks were not comparable, however, and age-attenuation of the Pe was seen only in the more perceptual flanker task. For younger adults, it was Pe scalp topography that seemed to reflect task demands, being maximal over central parietal areas in the flanker task, but over very frontal areas in the source monitoring task. With respect to vagal tone, in the flanker task, neither the number of errors nor ERP amplitudes were predicted by baseline or on-task vagal tone measures. However, in the more difficult source memory task, lower VT was marginally associated with greater numbers of source memory errors in the older group. Thus, for older adults, relatively low levels of parasympathetic control over cardiac response coincided with poorer source memory discrimination. In both groups, lower levels of baseline VT were associated with larger amplitude ERNs, and smaller amplitude Pe's. Thus, low VT was associated in a conceptual task with a greater "emergency response" to errors, and at the same time, reduced awareness of having made them. The efficiency of an individual's complex cognitive processing was therefore associated with the flexibility of parasympathetic control of heart rate, in response to a cognitively challenging task.
Resumo:
The successful development of stable biosensors incorporating entrapped proteins suffers from poor understanding of the properties of the entrapped biomolecules. This thesis reports on the use of fluorescence spectroscopy to investigate the properties of proteins entrapped in sol-gel processed silicate materials. Two different single tryptophan (Trp) proteins were investigated in this thesis, the Ca2 + binding protein cod III parvalbumin (C3P) and the salicylate binding protein human serum albumin (HSA). Furthermore, the reactive single cysteine (Cys) residue within C3P and HSA were labelled with the probes iodoacetoxynitrobenzoxadiazole (C3P) and acrylodan (C3P and HSA) to further examine the structure, stability and function of the free and entrapped proteins. The results show that both C3P and HSA can be successfully entrapped into sol-gelderived matrices with retention of function and conformational flexibility.
Resumo:
Two groups of nonmaternal day care providers, one made up of in-horne caregivers, and the other of providers of day care in centres, were asked to focus on their goals for the children in their care. A group of kindergarten teachers was asked to consider any differences they noticed in children in· the two types of day care mentioned above. It was found that in-horne caregivers, through flexibility, meet the developmental goals of the children in their care. Providers of tlay care in centres used a more structured and social program in order to meet the overall developmental goals for the children in their care. It was found that the kindergarten teachers noticed differences in the children in their classes in terms of their attitude and social behaviour. The type and quality of care were seen as possible influences on this outlook of young children in kindergarten. The one common element that each group highlighted with respect to the effects of day care at the kindergarten level was the important role of the family in the child's development not only in day care, but also in kindergarten class. There is still a strong need to determine the effects of various types of day care at all levels, and specifically at the kindergarten level. The more the kindergarten teacher is able to understand about the child's day care experience, and his or her own life,the better off these children in day care will be. This study confirmed both the importance of quality in child care, and the important role of the family in the child care decision.
Resumo:
This qualitative study examines teachers' experiences implementing new standardized curricula in Ontario schools. This new curricula contained several policy changes and an expectations based format which directed what knowledge and skills students were to demonstrate in each subject. This level of specificity of subject-content served to control teachers in relation to curricula; however, data suggested that at the same time, teachers had enormous flexibility in terms of pedagogy. Four secondary teachers who were implementing a Grade 10 course in the 2000-2001 school year participated in the study. The qualitative framework supported the researcher's emphasis on examining the participants' perspectives on the implementation of expectation-based curricula. Data collected included transcripts from interviews conducted with teacher participants and a representative of the Ontario Ministry of Education and Training, field notes, and a research journal. Many of the factors often cited in the literature as influencing implementation practices were found to have affected the participants' experiences of curriculum implementation: time, professional development, and teachers' beliefs, particularly concerning students. In addition, the format of the policy documents proved to both control and free teachers during the implementation process. Participants believed that the number of specific expectations did not provide them an opportunity to add content to the curriculum; at the same time, teachers also noted that the general format of the policy document allowed them to direct instruction to match students' needs and their own teaching preferences. Alignment between teachers' beliefs about education and their understanding of the new curriculum affected the ways in which many participants adapted during the implementation process.
Resumo:
Twenty-six sedentary, college-aged females were matched and randomly assigned to one of two groups. The massed group (n=13) completed 15 maximal isometric elbow flexion strength trials in one session, while the distributed group (n=13) performed five such contractions on three successive days. After a two-week and three month rest interval, both groups returned to perfonn another five maximal isometric elbow flexion strength trials to assess retention of any potential strength gains. Elbow flexion torque and surface electromyography (SEMG) of the biceps and triceps were monitored concurrently. There was a significant (P < 0.05) increase in strength in both groups from block one (first five contractions) to block four (first retest) and from block one to block five (second retest). Both groups exhibited a similar linear increasing (P < 0.05) trend in biceps root-mean-square (RMS) SEMG amplitude. A significant (P < 0.05) decrease in triceps RMS SEMG amplitude was found between block one and block four for the distributed group. However, a significant (P < 0.05) increase was then found between block one and five for the massed group, and between blocks four and five for distributed group. These results suggest that there is flexibility in resistive exercise schedules. An increase in neural drive to the agonist muscle continued throughout testing. This was accompanied by a reduction in antagonist co activation that was a short-tenn (two weeks) training effect, dissipated over the longer rest interval (three months).
Resumo:
This thesis will introduce a new strongly typed programming language utilizing Self types, named Win--*Foy, along with a suitable user interface designed specifically to highlight language features. The need for such a programming language is based on deficiencies found in programming languages that support both Self types and subtyping. Subtyping is a concept that is taken for granted by most software engineers programming in object-oriented languages. Subtyping supports subsumption but it does not support the inheritance of binary methods. Binary methods contain an argument of type Self, the same type as the object itself, in a contravariant position, i.e. as a parameter. There are several arguments in favour of introducing Self types into a programming language (11. This rationale led to the development of a relation that has become known as matching [4, 5). The matching relation does not support subsumption, however, it does support the inheritance of binary methods. Two forms of matching have been proposed (lJ. Specifically, these relations are known as higher-order matching and I-bound matching. Previous research on these relations indicates that the higher-order matching relation is both reflexive and transitive whereas the f-bound matching is reflexive but not transitive (7]. The higher-order matching relation provides significant flexibility regarding inheritance of methods that utilize or return values of the same type. This flexibility, in certain situations, can restrict the programmer from defining specific classes and methods which are based on constant values [21J. For this reason, the type This is used as a second reference to the type of the object that cannot, contrary to Self, be specialized in subclasses. F-bound matching allows a programmer to define a function that will work for all types of A', a subtype of an upper bound function of type A, with the result type being dependent on A'. The use of parametric polymorphism in f-bound matching provides a connection to subtyping in object-oriented languages. This thesis will contain two main sections. Firstly, significant details concerning deficiencies of the subtype relation and the need to introduce higher-order and f-bound matching relations into programming languages will be explored. Secondly, a new programming language named Win--*Foy Functional Object-Oriented Programming Language has been created, along with a suitable user interface, in order to facilitate experimentation by programmers regarding the matching relation. The construction of the programming language and the user interface will be explained in detail.
Resumo:
We examined the cognitive and emotional sequelae following mild head injury (MHI; e.g., concussion) in high-functioning individuals and whether persons with MHI pre~ent, both physiologically and via self-report, in a manner different from (i.e., underaroused) that of persons who have no history of head injury. We also investigated the effect arousal state ~as on the cognitive performance of this population. Using a quasiexperimental research design (N = 91), we examined changes in attention, working memory, and cognitive flexibility (subtests ofthe WAIS-III, 1997,WMS-III, 1997, & DKEFS, 2002) as a function of manipulated arousal (i.e., induced psychosocial stress/activation; reduced activation/relaxation). In addition to self-reported arousal and state anxiety (State-Trait Anxiety Inventory; Speilberger, 1983a) measures, physiological indices of arousal state (i.e., electrodermal responsivity, heart rate, and respiration activity) were recorded (via Polygraph Professional Suite, 2008) across a 2.5 hour interval while completing various cognitive tasks. Students also completed the Post-concussive Symptom Checklist (Gouvier et aI., 1992). The results demonstrate that university students who report a history ofMHI (i.e., "altered state of consciousness") experience significantly lower levels of anxiety, were physiologically underaroused, and were less responsive to stressors in their environment, compared to their non-~HI cohorts. As expected, cognitive flexibility (but not other neuropsychological measures of cognition) was advantaged with increased stress, and disadvantaged with reduced stress, in persons with reported MHI, but not for those without reported MHI which provided limited support for our hypothesis. Further, university students who had no complaints related to their previous MHI endorsed a greater number of traditional post-concussive symptoms in terms of intensity, duration and frequency as compared to students who did not report a MHI. The underarousal in traumatic brain injury has been associated with (ventromedial prefrontal cortex) VMPFC disruption and may be implicated in MHI generally. Students who report sustaining a previous MHI may be less able to physiologically respond and/or cognitively appraise, stressful experiences as compared to their no-MHI cohort and experience persistent, long-lasting consequences despite the subtle nature of a history of head injury.
Resumo:
Second-rank tensor interactions, such as quadrupolar interactions between the spin- 1 deuterium nuclei and the electric field gradients created by chemical bonds, are affected by rapid random molecular motions that modulate the orientation of the molecule with respect to the external magnetic field. In biological and model membrane systems, where a distribution of dynamically averaged anisotropies (quadrupolar splittings, chemical shift anisotropies, etc.) is present and where, in addition, various parts of the sample may undergo a partial magnetic alignment, the numerical analysis of the resulting Nuclear Magnetic Resonance (NMR) spectra is a mathematically ill-posed problem. However, numerical methods (de-Pakeing, Tikhonov regularization) exist that allow for a simultaneous determination of both the anisotropy and orientational distributions. An additional complication arises when relaxation is taken into account. This work presents a method of obtaining the orientation dependence of the relaxation rates that can be used for the analysis of the molecular motions on a broad range of time scales. An arbitrary set of exponential decay rates is described by a three-term truncated Legendre polynomial expansion in the orientation dependence, as appropriate for a second-rank tensor interaction, and a linear approximation to the individual decay rates is made. Thus a severe numerical instability caused by the presence of noise in the experimental data is avoided. At the same time, enough flexibility in the inversion algorithm is retained to achieve a meaningful mapping from raw experimental data to a set of intermediate, model-free
Resumo:
This study investigated the needs of adult ESL learners intending to pursue higher education in Canada. Its chief purpose was to enable educators and administrators to design ESL programs that would prepare students to function at optimal levels in academic and social settings during their university studies. The study adopted a mixed research method that was predominantly qualitative in its orientation and narrative in its implementation. It focused on an Intensive English Language Program (IELP) offered at an Ontario university. Using a holistic approach, the study sought to represent the various perspectives of all the participants in the program: the students, the instructors, and the administrators. Analysis of both qualitative and quantitative data gathered from 17 students, 6 instructors, and 1 administrator in the IELP showed that to a large extent the academic needs ofESL learners in the IELP were generally not being met. Most notably, the study found that learners were not receiving sufficient training in speaking and listening skills, a factor that contributed to their sense of insecurity and lack of confidence in their ability to communicate successfully in academic and social settings. The study also revealed that the solutions to many of the problems it identified lay not in the classroom but in the way the ESL program was structured administratively. One major recommendation to come out of the study is that programs like the IELP should be restructured so as to give them greater flexibility in meeting individual needs. While the study labored under certain limitations and did not achieve all of its goals, it did succeed in creating awareness ofthe problems and in establishing a methodological approach that can serve as a framework within which future research may be conducted in this somewhat neglected area.