893 resultados para Division.
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An article challenging the frequent assumption that Roman public libraries consisted of architecturally separated spaces divided by language (Latin and Greek). While the evidence for such a division is reasonably strong in some cases, in others it is convention rather than evidence that prompts the labelling of buildings as 'Latin' and 'Greek' libraries. The article is based on a paper given at a major international conference in Paris
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The possibility that parents of one sex may preferentially invest in offspring of a certain sex raises profound evolutionary questions about the relative worth of sons and daughters to their mothers and fathers. Post-fledging brood division-in which cacti parent feeds a different subset of offspring-has been well documented in birds. However, a lack of empirical evidence that this may be based oil offspring sex, combined with the theoretical difficulty of explaining such an interaction, has led researchers to consider a gender bias in post-fledging brood division highly unlikely. Here we show that in the toc-toc, Foudia sechellarum, postfledging brood division is extreme and determined by sex; where brood composition allows, male parents exclusively provision male fledglings, whereas female parents provision female fledglings. This is the first study to provide unambiguous evidence, based on molecular sexing, that sex-biased post-fledging brood division can occur in birds. Male and female parents provisioned at the same rate and neither offspring nor parent survival appeared to be affected by the sex of the parent or offspring, respectively. The current hypotheses predicting advantages for brood division and preferential care for one specific type of offspring are discussed in the light of our results.
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The distributions of times to first cell division were determined for populations of Escherichia coli stationary-phase cells inoculated onto agar media. This was accomplished by using automated analysis of digital images of individual cells growing on agar and calculation of the "box area ratio." Using approximately 300 cells per experiment, the mean time to first division and standard deviation for cells grown in liquid medium at 37 degrees C and inoculated on agar and incubated at 20 degrees C were determined as 3.0 h and 0.7 h, respectively. Distributions were observed to tail toward the higher values, but no definitive model distribution was identified. Both preinoculation stress by heating cultures at 50 degrees C and postinoculation stress by growth in the presence of higher concentrations of NaCl increased mean times to first division. Both stresses also resulted in an increase in the spread of the distributions that was proportional to the mean division time, the coefficient of variation being constant at approximately 0.2 in all cases. The "relative division time," which is the time to first division for individual cells expressed in terms of the cell size doubling time, was used as measure of the "work to be done" to prepare for cell division. Relative division times were greater for heat-stressed cells than for those growing under osmotic stress.
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A method is presented for determining the time to first division of individual bacterial cells growing on agar media. Bacteria were inoculated onto agar-coated slides and viewed by phase-contrast microscopy. Digital images of the growing bacteria were captured at intervals and the time to first division estimated by calculating the "box area ratio". This is the area of the smallest rectangle that can be drawn around an object, divided by the area of the object itself. The box area ratios of cells were found to increase suddenly during growth at a time that correlated with cell division as estimated by visual inspection of the digital images. This was caused by a change in the orientation of the two daughter cells that occurred when sufficient flexibility arose at their point of attachment. This method was used successfully to generate lag time distributions for populations of Escherichia coli, Listeria monocytogenes and Pseudomonas aeruginosa, but did not work with the coccoid organism Staphylococcus aureus. This method provides an objective measure of the time to first cell division, whilst automation of the data processing allows a large number of cells to be examined per experiment. (c) 2005 Elsevier B.V. All rights reserved.
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The subcellular localization of transmissible gastroenteritis virus (TGEV) and mouse hepatitis virus (MHV) (group I and group II coronaviruses, respectively) nucleoproteins (N proteins) were examined by confocal microscopy. The proteins were shown to localize either to the cytoplasm alone or to the cytoplasm and a structure in the nucleus. This feature was confirmed to be the nucleolus by using specific antibodies to nucleolin, a major component of the nucleolus, and by confocal microscopy to image sections through a cell expressing N protein. These findings are consistent with our previous report for infectious bronchitis virus (group III coronavirus) (J. A. Hiscox et al., J. Virol. 75:506-512, 2001), indicating that nucleolar localization of the N protein is a common feature of the coronavirus family and is possibly of functional significance. Nucleolar localization signals were identified in the domain III region of the N protein from all three coronavirus groups, and this suggested that transport of N protein to the nucleus might be an active process. In addition, our results suggest that the N protein might function to disrupt cell division. Thus, we observed that approximately 30% of cells transfected with the N protein appeared to be undergoing cell division. The most likely explanation for this is that the N protein induced a cell cycle delay or arrest, most likely in the G2/M phase. In a fraction of transfected cells expressing coronavirus N proteins, we observed multinucleate cells and dividing cells with nucleoli (which are only present during interphase). These findings are consistent with the possible inhibition of cytokinesis in these cells.
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Reductions in the division of labour are a significant feature of modern developments in work organisation. It has been recognised that a reduced division of labour can have the advantages of job enrichment and lower coordination costs. In this paper it is shown how advantages from a lesser division of labour can stem from the flow of work between different sets of resources where the work rates of individual production stages are subject to uncertainties. Both process and project-based work are considered. Implications for the boundaries of the firm and for innovation processes are noted.
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Review essay on literature on the role of Germany in the Cold War
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Purpose – While the charity retail literature emphasizes the richness of human resource practices among charity retailers, it rarely makes the link between these practices and their interest for establishing charity retailers' brands. Simultaneously, while the retail branding literature increasingly emphasizes the central role of human resource practices for retail branding, it rarely explains how retailers should conduct such practices. The purpose of this study is to test the recent model proposed by Burt and Sparks in 2002 (the “fifth generation of retail branding”) which proposes that a retail brand depends on the alignment between a retailer's substance (vision and culture) and its perceived image by customers. Design/methodology/approach – The research is based on an ethnographic study conducted within the Oxfam Trading Division, GB from October to December 2002. Findings – The study supports the Burt and Spark's model and makes explicit the practice of human resource for branding. The study demonstrates that it was the alignment between the vision of Oxfam's top management and its new customer‐oriented culture, two elements of its core substance mediated to customers by store employees, which has enabled an improved customers' perception of the brand. The study also seeks to elaborate upon the Burt and Spark's model by specifying an ascending feedback loop starting from customers' perception of Oxfam brand and enabling the creation of a suitable culture and vision again mediated by store employees. Research limitations/implications – New research should explore whether and how retailers create synergies between human resource and marketing functions to sustain their brand image. Practical implications – If the adoption of business practices by charity retailers is often discussed, this study highlights that commercial retailers could usefully transfer human resource best practices from leading charity retailers to develop their retail brand. Originality/value – The paper is of value to commercial retailers.
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Purpose – The purpose of this paper is to demonstrate how strategy is developed and implemented within a subsidiary of a global organization, the relationship between subsidiary and headquarters and the need for continuous change and adaption to remain relevant. Furthermore, this case study describes a successful process of invention and adoption. Design/methodology/approach – The paper draws on documentary evidence and a semistructured interview with Jill McDonald CEO and President of McDonald’s Northern Europe Division with responsibility for the UK, Sweden, Finland, Denmark, Norway and the Republic of Ireland. Management research rarely captures the views of the top executive, yet the top executives have a broad picture and are key strategic decision makers. Findings – The case study and interview offers a unique insight into factors contributing to McDonald’s unprecedented success (it has paid an increased dividend for the past 37 years). It also sheds light on its successful internationalization strategy. Originality/value – The case study draws on published material and augments this with an in-depth interview with the Chief Executive. Very few case studies offer insight into the thinking of a Chief Executive managing a subsidiary of a global organization. Its value lies in the lessons that managers and students of management can draw on the approach adopted by a highly successful global organization.
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The leaf is considered the most important vegetative organ of tank epiphytic bromeliads due to its ability to absorb and assimilate nutrients. However, little is known about the physiological characteristics of nutrient uptake and assimilation. In order to better understand the mechanisms utilized by some tank epiphytic bromeliads to optimize the nitrogen acquisition and assimilation, a study was proposed to verify the existence of a differential capacity to assimilate nitrogen in different leaf portions. The experiments were conducted using young plants of Vriesea gigantea. A nutrient solution containing NO(3)(-)/NH(4)(+) or urea as the sole nitrogen source was supplied to the tank of these plants and the activities of urease, nitrate reductase (NR), glutamine synthetase (GS) and glutamate dehydrogenase (NADH-GDH) were quantified in apical and basal leaf portions after 1, 3, 6, 9, 12, 24 and 48 h. The endogenous ammonium and urea contents were also analyzed. Independent of the nitrogen sources utilized, NR and urease activities were higher in the basal portions of leaves in all the period analyzed. On the contrary. GS and GDH activities were higher in apical part. It was also observed that the endogenous ammonium and urea had the highest contents detected in the basal region. These results suggest that the basal portion was preferentially involved in nitrate reduction and urea hydrolysis, while the apical region could be the main area responsible for ammonium assimilation through the action of GS and GDH activities. Moreover, it was possible to infer that ammonium may be transported from the base, to the apex of the leaves. In conclusion, it was suggested that a spatial and functional division in nitrogen absorption and NH(4)(+) assimilation between basal and apical leaf areas exists, ensuring that the majority of nitrogen available inside the tank is quickly used by bromeliad`s leaves. (C) 2011 Elsevier GmbH. All rights reserved.