18 resultados para Large Mammals

em Brock University, Canada


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This study explored the concept of a spiritual retreat for frontline employees of a large corporate call centre. During a 1 day retreat, 4 call centre employees were introduced to various meditation and retreat activities. Follovsdng the retreat the participants were asked to incorporate the various meditations and activities into their workplace. The participants kept journals throughout the study in an effort to determine what occurred when these practices were transferred from the retreat setting to the workplace. This study examined how a working spirituality enhances one's sense of fulfillment, defined by certain critical elements: relationship, awareness, ritual, internal commitment, and choice. Although the retreat was a successful means of exploring these elements, the degree to which each employee could benefit from them was determined by the extent of their internal commitment not only to themselves, but also to their jobs.

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A detailed theoretical investigation of the large amplitude motions in the S, excited electronic state of formic acid (HCOOH) was done. This study focussed on the the S, «- So electronic band system of formic acid (HCOOH). The torsion and wagging large amplitude motions of the S, were considered in detail. The potential surfaces were simulated using RHF/UHF ab-initio calculations for the two electronic states. The energy levels were evaluated by the variational method using free rotor basis functions for the torsional coordinates and harmonic oscillator basis functions for the wagging coordinates. The simulated spectrum was compared to the slit-jet-cooled fluorescence excitation spectrum allowing for the assignment of several vibronic bands. A rotational analysis of certain bands predicted that the individual bands are a mixture of rotational a, b and c-type components.The electronically allowed transition results in the c-type or Franck-Condon band and the electronically forbidden, but vibronically allowed transition creates the a/b-type or Herzberg-Teller components. The inversion splitting between these two band types differs for each band. The analysis was able to predict the ratio of the a, b and c-type components of each band.

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Large carpenter bees (Hymenoptera: Apidae: Xylocopa) have traditionally been thought of as exhibiting solitary or occasionally communal colony social organization. However, studies have demonstrated more complex fonns of social behaviour in this genus. In this document, I examine elements ofbehaviour and life history in a North American species at the northern extreme of its range. Xylocopa virginica was found to be socially polymorphic with both solitary and meta-social or semi-social nests in the same population. In social nests, there is no apparent benefit from additional females which do not perfonn significant work or guarding. I found that the timing of life-history events varies between years, yet foraging effort only differed in the coldest and wettest year of2004 the study. Finally, I that male X virginica exhibit female defence polygyny, with resident and satellite males. Resident males maintain their territories through greater aggression relative to satellites.

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This qualitative study investigated how a team of 7 hospital educators collaborated to develop e-curriculum units to pilot for a newly acquired learning -r management system at a large, multisite academic health sciences centre. A case study approach was used to examine how the e-Curriculum Team was structured, how the educators worked together to develop strategies to better utilize e-leaming in their ovwi practice, what e-curriculum they chose to develop, and how they determined their priorities for e-curriculum development. It also inquired into how they planned to involve other educators in using e-leaming. One set of semistructured interviews with the 6 hospital educators involved in the project, as well as minutes of team meetings and the researcher's journal, were analyzed (the researcher was also a hospital educator on the team). Project management structure, educator support, and organizational pressures on the implementation project feature prominently in the case study. This study suggests that implementation of e-leaming will be more successful if (a) educators involved in the development of e-leaming curriculum are supported in their role as change agents, (b) the pain of vmleaming current educational practice is considered, (c) the limitations of the software being implemented are recognized, (d) time is spent leaming about best practice, and (e) the project is protected as much as possible from organizational pressures and distractions.

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Abstract Many species of social insects have the ability to recognize their nestmates. In bees, sociality is maintained by bees that recognize which individuals should be helped and which should be hanned in order to maximize fitness (either inclusive or individual) (Hamilton 1964; Lin and Michener 1972). Since female bees generally lay eggs in a single nest, it is highly likely that bees found cohabitating in the same nest are siblings. According to the kin selection hypothesis, individuals should cooperate and avoid aggression with same sex nestmates (Hamilton 1964). However, in opposite sex pairs that are likely kin, aggression should increase among nestmates as an expression of inbreeding avoidance (Lihoreau et al. 2007). Female bees often guard nest entrances, recognizing and excluding foreign conspecific females that threaten to steal nest resources (Breed and Page 1991). Conversely, males that aggressively guard territories should avoid aggression towards other males that are likely kin (Shellman-Reeve and Gamboa 1984). In order to test whether Xy/ocopa virginica can distinguish nestmates from non-nestmates, circle tube testing arenas were used. Measures of aggression, cooperation and tolerance were evaluated to detennine the presence of nestmate recognition in this species. The results of this study indicate that male and female X virginica have the ability to distinguish nestmates from non-nestmates. Individuals in same sex pairs demonstrated increased pushing, biting, and C-posturing when faced with non-nestmates. Males in same sex pairs also attempted to pass (unsuccessfully) nOIl-nestmates more often than ncstmates, suggesting that this behaviour may be an cxpression of dominancc in males. Increased cooperation exemplified by successful passes was not observed among nestmates. However, incrcased tolerance in the [onn of head-to-head touching was observed for nestmates in female same sex and opposite sex pairs. These results supported the kin selection hypothesis. Moreover, increased tolerance among opposite sex non-nestmates suggested that X virginica do not demonstrate inbreeding avoidance among nestmates. 3 The second part of this study was conducted to establish the presence and extent of drifting, or travelling to different nests, in a Xylocopa virgillica population. Drifting in flying Hymenoptera is reported to be the result of navigation error and guard bees erroneously admitting novel individuals into the nest (Michener 1966). Since bees in this study were individually marked and captured at nest entrances, the locations where individuals were caught allowed me to determine where and how often bees travelled from nest to nest. Ifbees were captured near their home nests, changing nests may have been deliberate or explained by navigational error. However, ifbees were found in nests further away from their homes, this provides stronger evidence that flying towards a novel nest may have been deliberate. Female bees are often faithful to their own nests (Kasuya 1981) and no drifting was expected in female X virginica because they raise brood and contribute to nest maintenance activities. Contrary to females, males were not expected to remain faithful to a single nest. Results showed that many more females drifted than expected and that they were most often recaptured in a single nest, either their home nest or a novel nest. There were some females that were never caught in the same nest twice. In addition, females drifted to further nests when population density was low (in 2007), suggesting they seek out and claim nesting spaces when they are available. Males, as expected, showed the opposite pattern and most males drifted from nest to nest, never recaptured in the same location. This pattern indicates that males may be nesting wherever space is available, or nesting in benches nearest to their territories. This study reveals that both female and male X virginica are capable of nestmate recognition and use this ability in a dynamic environment, where nest membership is not as stable as once thought.

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Cytoch ro me c oxidase (ferrocytochrome c : 02 oxidoreductase ; EC 1.9. 3.1) is the terminal enzyme in the mitochondrial electron transport chain, catalyzing the transfer of electrons from ferrocytochrome c to molecular oxygen. The effects of two large amphiphilic molecules .. valinomycin and dibucaine upon the spectra of the isolated enzyme and upon the activity of both isolated enzyme and enzyme in membrane systems are investigated by using spectrophotometric and oxygen electrode techniques. The results show that both valinomycin and dibucaine change the Soret region of the spectrum and cause a partial inhibition in a concentration range higher than that in which they act as ionophores. It is concluded that both valinomycin and dibucain~ binding induce a conformational change of the protein structure which modifies the spectrum of the a3 CUB centre and diminishes the rate of electron transfer between cytochrome a and the binuclear centre.

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How does fire affect the plant and animal community of the boreal forest? This study attempted to examine the changes in plant composition and productivity, and small mammal demography brought about by fire in the northern boreal environment at Chick Lake, N.W.T. (65053fN, 128°14,W). Two 5*6 ha plots measuring 375m x 150m were selected for study during the summers of 1973 and 197^. One had been unburned for 120 years, the other was part of a fire which burned in the spring of 1969. Grids of 15m x 15m were established in each plot and meter square quadrats taken at each of the 250 grid intersections in order to determine plant composition and density. Aerial primary production was assessed by clipping and drying 80 samples of terminal new production for each species under investigation. Small mammal populations were sampled by placing a Sherman live trap at each grid intersection for ten days in every month. The two plots were similar in plant species composition which suggested that most regrowth in the burned area was from rootstocks which survived the fire. The plant data were submitted to a cluster analysis that revealed nine separate species associations, six of which occured in the burned area and eight of which occured in the control. These were subsequently treated as habitats for purposes of comparison with small mammal distributions. The burned area showed a greater productivity in flowers and fruits although total productivity in the control area was higher due to a large contribution from the non-vascular component. Maximum aerial productivity as dry wieght was measured at 157.1 g/m and 207.8 g/m for the burn and control respectively. Microtus pennsylvanicus and Clethrionomys rutilus were the two most common small mammals encountered; Microtus xanthognathus, Synaptomys borealis, and Phenacomys intermedius also occured in the area. Populations of M. pennsylvanicus and C. rutilus were high during the summer of 1973; however, M. pennsylvanicus was rare on the control but abundant on the burn, while C. rutilus was rare on the burn but abundant in the control. During the summer of 197^ populations declined, with the result that few voles of any species were caught in the burn while equal numbers of the two species were caught in the control. During the summer of 1973 M. pennsylvanicus showed a positive association to the most productive habitat type in the burn which was avoided by C. rutilus. In the control £• rutilus showed a similar positive association to the most productive habitat type which was avoided by M. pennsylvanicus. In all cases for the high population year of 1973# the two species never overlapped in habitat preference. When populations declined in 197^f "both species showed a strong association for the most productive habitat in the control. This would suggest that during a high population year, an abundant species can exclude competitors from a chosen habitat, but that this dominance decreases as population levels decrease. It is possible that M. pennsylvanicus is a more efficient competitor in a recently burned environment, while C. rutilus assumes this role once non-vascular regrowth becomes extensive.

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Genetic chimeras made by aggregating early mouse embryos have many uses in developmental biology and have also provided insights into embryonic growth regulation. There is an indication that the embryo can regulate for an increase in size because although aggregation chimeras are twice as big as normal embryos when made, they are born of normal size. Upward regula..... tion of size reduced embryos is also possible. Half embryos made by the isolation or destruction of one of the blastomeres of a 2-cell embryo are also born of normal size. Little is known about the timing or the mechanism of this size regulation. In this study, the timing of size regulation in double and half embryos was clearly established by comparison of cell numbers derived from serial reconstruction of light microscope sections of control and experimental embryos. It was shown that size regulation in double embryos occurred around 6dl6h and in half embryos by 7dOh. Size regulation occurred in all tissues at the same time indicating a single control mechanism for the entire embryo. More detailed examination of the growth of double embryos revealed that size regulation occurred by alteration in cell cycle length~ No excessive cell death was found in double embryos compared to the controls and continuous labelling with [3H] thymidine showed no large non-dividing cell population in double embryos. However, a comparison of the mitotic index of double and control embryos after colcemid treatment, revealed a large difference between the two around 5dl6h to 6d16h. During this period, control embryos underwent a proliferative burst not shown by the double embryos. The mechanism for cell cycle control is not clear; it may be intrinsic to the embryo or determined by the uterine environment. Evidence was found suggesting that differentiation in the postimplantation embryo was cell number dependent. The timing of differentiative events was examined in half, double and control embryos. Proamnion formation, which occurs prior to size regulation, occurs at the same cell number but at different times in the three groups of embryos. However mesoderm which appears after size regulation was seen at the same time in all grollps of embryos.

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Cytoch ro me c oxidase (ferrocytochrome c : 02 oxidoreductase ; EC 1.9. 3.1) is the terminal enzyme in the mitochondrial electron transport chain, catalyzing the transfer of electrons from ferrocytochrome c to molecular oxygen. The effects of two large amphiphilic molecules - valinomycin and dibucaine upon the spectra of the isolated enzyme and upon the activity of both isolated enzyme and enzyme in membrane systems are investigated by using spectrophotometric and oxygen electrode techniques. The results show that both valinomycin and dibucaine change the Soret region of the speetrum and cause a partial inhibition in a concentration range higher than that in which they act as ionophores. It is concluded that both valinomycin and dibucaine binding induce a conformational change of the protein structure which modifies the spectrum of the a3 CUB centre and diminishes the rate of electron transfer between cytochrome a and the binuclear centre.

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Complex networks have recently attracted a significant amount of research attention due to their ability to model real world phenomena. One important problem often encountered is to limit diffusive processes spread over the network, for example mitigating pandemic disease or computer virus spread. A number of problem formulations have been proposed that aim to solve such problems based on desired network characteristics, such as maintaining the largest network component after node removal. The recently formulated critical node detection problem aims to remove a small subset of vertices from the network such that the residual network has minimum pairwise connectivity. Unfortunately, the problem is NP-hard and also the number of constraints is cubic in number of vertices, making very large scale problems impossible to solve with traditional mathematical programming techniques. Even many approximation algorithm strategies such as dynamic programming, evolutionary algorithms, etc. all are unusable for networks that contain thousands to millions of vertices. A computationally efficient and simple approach is required in such circumstances, but none currently exist. In this thesis, such an algorithm is proposed. The methodology is based on a depth-first search traversal of the network, and a specially designed ranking function that considers information local to each vertex. Due to the variety of network structures, a number of characteristics must be taken into consideration and combined into a single rank that measures the utility of removing each vertex. Since removing a vertex in sequential fashion impacts the network structure, an efficient post-processing algorithm is also proposed to quickly re-rank vertices. Experiments on a range of common complex network models with varying number of vertices are considered, in addition to real world networks. The proposed algorithm, DFSH, is shown to be highly competitive and often outperforms existing strategies such as Google PageRank for minimizing pairwise connectivity.

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A large group of men in hard hats in the tunnel. The names of the men are unknown.

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Large group of men standing in the tunnel wearing boots and hard hats.

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The interior layered deposit (ILD) in Ganges Chasma, Valles Marineris, is a 4.25 km high mound that extends approximately 110 km from west to east. The deposition, deformation, and erosion history of the Ganges ILD records aids in identifying the processes that formed and shaped the Chasma. To interpret structural and geomorphic processes acting on the ILD, multiple layer attitudes and layer thickness transects were conducted on the Ganges ILD. Mineralogical data was analyzed to determine correlations between materials and landforms. Layer thickness measurements indicate that the majority of layers are between 0.5 m and 4 m throughout the ILD. Three major benches dominate the Ganges ILD. Layer thicknesses increase at the ILD benches, suggesting that the benches are formed from the gradual thickening of layers. This indicates that the benches are depositional features draping over basement topography. Layer attitudes indicate overall shallow dips generally confined to a North-South direction that locally appear to follow bench topography. Layering is disrupted on a scale of 40 m to 150 m in 12 separate locations throughout the ILD. In all locations, underlying layering is disturbed by overlying folded layers in a trough-like geometry. These features are interpreted to have formed as submarine channels in a lacustrine setting, subsequently infilled by sediments. Subsequently, the channels were eroded to the present topography, resulting in the thin, curved layering observed. Data cannot conclusively support one ILD formation hypothesis, but does indicate that the Ganges ILD postdates Chasma formation. The presence of water altered minerals, consistently thin layering, and layer orientations provide strong evidence that the ILD formed in a lacustrine setting.

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A woman wearing a hat and holding a small purse. She is standing next to a large tree trunk and there are benches behind her.