996 resultados para Relative degree n


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The first graduate, John Auld, receives his convocation hood from (?) during the first ever Convocation held at Brock in 1967. Chancellor R. L. Hearn stands in front of John Auld.

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Individuals with disabiliiies are increasingly accessing post secondary education opportunities to further develop their educational and career goals. This study examines the current facilitative practices of Canadian university activity-based physical education degree programs on the participation of individuals with disabilities. A critical orientation and descriptive/interpretative approach allows insight into unique stories and experiences of physical education practitioners and special needs professionals as they attempt to provide equitable educational experiences within a least restrictive environment. Leading practitioners are used to triangulate and strengthen the validity of the data while providing direction and advocacy for future development and inclusion of individuals with disabilities. The study concludes with seven recommendations, each providing university activity-based physical education degree programs with viable opportunities for helping create equitable opportunities for individuals with disabilities.

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The purpose of this qualitative research study was to foster an understanding of the rehabilitation counselling practice offamilies of the brain-injured. Specifically, the study explores the perceptions of stakeholders in regards to the degree of satisfaction with the quality of service received. Questionnaires were administered, and semi-structured, openended interviews were conducted, with six participating families (n=8). Preliminary data were collected via two instruments: (i) the Family Participant Questionnaire, consisting of participants' sample characteristics, information pertaining to the history of the family, details of the injury, and information relating to the type, use, and need offamily services utilized; and (ii) the Community Integration Questionnaire, a measurement of the degree of social displacementllevel of community integration of the injured family member. Utilizing the procedural steps outlined by Colaizzi's (1978) method of protocol analysis, recommendations for a future program based on related and current family needs are discussed in detail. Substantiating and supporting information are offered to rehabilitation practitioners, educational planners, and policymakers alike, concerning the degree of satisfaction with rehabilitative service, and the means of improving upon the overall quality of health care to families of the brain-injured. Implications for clinical practice and research are also raised for discussion.

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Mammalian heterotherms, such as hibemators, are known to be more tolerant of low oxygen tensions than their homeothermic counterparts. It has been suggested that this relative hypoxia tolerance is related to their ability to deal with dramatic changes in body temperature during entry to and arousal from torpor. However, hibemators demonstrate dramatic seasonality in both daily heterothermy and overall torpor expression. It was of interest to test if seasonal comparisons of normothermic individuals within a single species with the capacity to hibernate produce changes in the response to hypoxia that would reflect a seasonal change in tolerance to low oxygen. In particular, the species studied, the Eastern chipmunk {Tamias striatus), is known to enter into torpor exclusively in the winter. To test for seasonal differences in the metabolic and thermoregulatory responses to hypoxia, flow-through respirometry was used to compare metabolic rate, minimum thermal conductance, body temperature, and a thermal gradient used to assess selected ambient temperature in response to hypoxia in both summer and winter acclimated animals. Although the animals periodically expressed torpor throughout the winter, no differences between season in resting metabolic rate, body temperature or minimum thermal conductance were observed in normoxia. The metabolic trials indicated that chipmunks are less responsive to hypoxia in the winter than they are in the summer. Although body temperature dropped in response to hypoxia in both seasons, the decrease was less in the winter, and there was no corresponding decrease in metabolic rate. Providing the animals with a choice of ambient temperatures in hypoxia resulted in a blunting of the drop in body temperature in both seasons, suggesting that the reported fall in body temperature set point in hypoxia is not fully manifested in the behavioural pathways responsible for thermoregulation in chipmunks. Instead, body temperature in hypoxia appears to be highly dependent on ambient temperature and oxygen concentration. The results of this study suggest that the season in which the responses to hypoxia are measured is important, especially in a heterotherm where seasonality can affect the degree to 1 which the animal is tolerant of hypoxia. Winter-acclimated chipmunks appear more capable of defending metabolic heat production in hypoxia, a response consistent with the increased thermogenic capacity observed in animals that must periodically enter and arouse from torpor during hibernation.

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A comprehensive elemental, isotopic and microstructural analyses was undertaken of brachiopod calcites from the Hamilton Group (Middle Devonian), Clinton Group (Middle Silurian) and Middle to Upper Ordovician strata of Ontario and New York State. The majority of specimens were microstructurally and chemically preserved in a pristine state, although a number of specimens show some degree of post-depositional alteration. Brachiopod calcites from the Hamilton and Clinton Groups were altered by marine derived waters whereas Trenton Group (Middle Ordovician) brachiopods altered in meteorically derived fluids. Analysis of the elemental and isotopic compositions of pristine Hamilton Group brachiopods indicates there are several chemical relationships inherent to brachiopod calcite. Taxonomic differentiation of Mg, Sr and Na contents was evident in three co-occuring species from the Hamilton Group. Mean Mg contents of pristine brachiopods were respectively Athyris spiriferoides (1309ppm), Mucrospirifer mucronatus (1035ppm) and Mediospirifer audacula (789ppm). Similarly, taxonomic differentiation of shell calcite compositions was observed in co-occuring brachiopods from the Clinton Group (Middle Silurian) and the Trenton Group (Middle Ordovician). The taxonomic control of elemental regulation into shell calcite is probably related to the slightly different physiological systems and secretory mechanisms. A relationship was observed in Hamilton Group species between the depth of respective brachiopod communities and their Mg, Sr and Na contents. These elements were depleted in the shell calcites of deeper brachiopods compared to their counterparts in shallower reaches. Apparently shell calcite elemental composition is related to environmental conditions of the depositional setting, which may have controlled the secretory regime, mineral morphology of shell calcite and precipitation rates of each species. Despite the change in Mg, Sr and Na contents between beds and formations in response to environmental conditions, the taxonomic differentiation of shell calcite composition is maintained. Thus, it may be possible to predict relative depth changes in paleoenvironmental reconstructions using brachiopod calcite. This relationship of brachiopod chemistry to depth was also tested within a transgressiveregressive (T-R) cycle in the Rochester Shale Formation (Middle Silurian). Decreasing Mg, Sr and Na contents were observed in the transition from the shallow carbonates of the Irondequoit Formation to the deeper shales of the lowest 2 m of Rochester Shale. However, no isotopic and elemental trends were observed within the entire T-R cycle which suggests that either the water conditions did not change significantly or that the cycle is illusory. A similar relationship was observed between the Fe and Mn chemistries of shell calcite and redox/paleo-oxygen conditions. Hamilton Group brachiopods analysed from deeper areas of the shelf are enriched in Mn and Fe relative to those from shallow zones. The presence of black shales and dysaerobic faunas, during deposition of the Hamilton Group, suggests that the waters of the northern Appalachian Basin were stratified. The deeper brachiopods were marginally positioned above an oxycline and their shell calcites reflect periodic incursions of oxygen depleted water. Furthermore, analysis of Dalmanella from the black shales of the Collingwood Shale (Upper Ordovician) in comparison to those from the carbonates of the Verulam Formation (Middle Ordovician) confirm the relationship of Fe and Mn contents to periodic but not permanent incursions of low oxygen waters. The isotopic compositions of brachiopod calcite found in Hamilton Group (813C; +2.5% 0 to +5.5% 0; 8180 -2.50/00 to -4.00/00) and Clinton Group (813C; +4.00/00 to +6.0; 8180; -1.8% 0 to -3.60/ 00) are heavier than previously reported. Uncorrected paleotemperatures (assuming normal salinity, 0% 0 SMOW and no fractionation effects) derived from these isotopic values suggest that the Clinton sea temperature (Middle Silurian) ranged from 18°C to 28°C and Hamilton seas (Middle Devonian) ranged between 24°C and 29°C. In addition, the isotopic variation of brachiopod shell calcite is significant and is related to environmental conditions. Within a single time-correlative shell bed (the Demissa Bed; Hamilton Group) a positive isotopic shift of 2-2.5% 0 in 013C compositions and a positive shift of 1.0-1.50/00 in 0180 composition of shell calcite is observed, corresponding with a deepening of brachiopod habitats toward the axis of the Appalachian Basin. Moroever, a faunal succession from deeper Ambocoelia dominated brachiopod association to a shallow Tropidoleptus dominated assocation is reflected by isotopic shifts of 1.0-1.50/00. Although, other studies have emphasized the significance of ±20/oo shifts in brachiopod isotopic compositions, the recognition of isotopic variability in brachiopod calcite within single beds and within depositional settings such as the Appalachian Basin has important implications for the interpretation of secular isotopic trends. A significant proportion of the variation observed isotopic distribution during the Paleozoic is related to environmental conditions within the depositional setting.

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Exchange reactions between molecular complexes and excess acid or base are well known and have been extensively surveyed in the literature(l). Since the exchange mechanism will, in some way involve the breaking of the labile donor-acceptor bond, it follows that a discussion of the factors relating to bonding in molecular complexes will be relevant. In general, a strong Lewis base and a strong Lewis acid form a stable adduct provided that certain stereochemical requirements are met. A strong Lewis base has the following characteristics (1),(2) (i) high electron density at the donor site. (ii) a non-bonded electron pair which has a low ionization potential (iii) electron donating substituents at the donor atom site. (iv) facile approach of the site of the Lewis base to the acceptor site as dictated by the steric hindrance of the substituents. Examples of typical Lewis bases are ethers, nitriles, ketones, alcohols, amines and phosphines. For a strong Lewis acid, the following properties are important:( i) low electron density at the acceptor site. (ii) electron withdrawing substituents. (iii) substituents which do not interfere with the close approach of the Lewis base. (iv) availability of a vacant orbital capable of accepting the lone electron pair of the donor atom. Examples of Lewis acids are the group III and IV halides such (M=B, AI, Ga, In) and MX4 - (M=Si, Ge, Sn, Pb). The relative bond strengths of molecular complexes have been investigated by:- (i) (ii) (iii) (iv) (v] (vi) dipole moment measurements (3). shifts of the carbonyl peaks in the IIIR. (4) ,(5), (6) .. NMR chemical shift data (4),(7),(8),(9). D.V. and visible spectrophotometric shifts (10),(11). equilibrium constant data (12), (13). heats of dissociation and heats of reactions (l~), (16), (17), (18), (19). Many experiments have bben carried out on boron trihalides in order to determine their relative acid strengths. Using pyridine, nitrobenzene, acetonitrile and trimethylamine as reference Lewis bases, it was found that the acid strength varied in order:RBx3 > BC1 3 >BF 3 • For the acetonitrile-boron trihalide and trimethylamine boron trihalide complexes in nitrobenzene, an-NMR study (7) showed that the shift to lower field was. greatest for the BB~3 adduct ~n~ smallest for the BF 3 which is in agreement with the acid strengths. If electronegativities of the substituents were the only important effect, and since c~ Br ,one would expect the electron density at the boron nucleus to vary as BF3nd therefore, the acid strength would vary as BF~BC1)BBr3: However, for the boron trihalides, the trend is in the opposite direction as determined experimentally. Considerable back-bonding (20), (21) between the halogen and the boron atoms has been proposed as the predominating factor, i.e. ~rt- back-bond between a lone electron pair on the halogen and the vacant orbital on the boron site. The degree of back-bonding varies inversely as the bo~on halogen distance and one would therefore expect the B-F bond to exhibit greater back-bonding character than the B-Cl or B-Br bonds. Since back-bonding transfers electron density from substituent to the boron atom site, this process would be expected to weaken the Lewis acid strength. This explains the Lewis acid strength increasing in the order BF 3 BC1 3 BBr 3 . When the acetonitrile boron trihalide complex is formed, the boron atom undergoes ~_cbange of hybridization from sp2 to sp3. From a linear relationship between the heat of formation of ethyl acetate adducts and the shift in the carbonyl I.R. stretch, Drago (22) et al have proposed that the angular di~tortion of the X-B-X bonds from sp2 (12 ) to sp3 (10 hybridization is proportional to the amount of charge transferred, i.e. to the nature of the base, and they have rejected the earlier concept of reorganization energy in explaining the formation of the adduct bond (19).