2 resultados para concept éthique dense

em QSpace: Queen's University - Canada


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Cystatin Related Epididymal Spermatogenic protein (CRES) is expressed in both the testis and epididymis and found associated with spermatozoa. It appears as non-glycosylated (14 and 12 kDa) and glycosylated isoforms (19 and 17 kDa). The role of CRES is enigmatic and dependent on localization of its isoforms, which is the objective of this study. The initial approach was to investigate testicular and epididymal origins of these isoforms by immunohistochemistry and immunogold cytochemistry. To further pinpoint CRES localization we then selectively extracted and fractionated epididymal spermatozoa in order to find by immunoblotting which sperm fractions contained CRES isoforms. Immunohistochemical analysis of mouse spermatogenesis showed that CRES was expressed in the tail cytoplasm of elongating spermatids from step 9-16, with a pattern reminiscent of outer dense fibre (ODF) proteins. Ultrastructural immunocytochemistry revealed that the immunogold label was concentrated over growing ODFs and mitochondrial sheath in the testes which persisted in spermatozoa through the epididymis. Sequential extractions of isolated sperm tails with Triton X-100-dithiothreitol (DTT) to remove the mitochondrial sheath, whose extract contained an unrelated 66 kDa immunoreactive band, followed by either sodium dodecyl sulfate (SDS)-DTT or urea-DTT to solubilise accessory fibres of the tail revealed a 14 kDa immunoreactive band associated with the ODF. In addition, Western blots revealed glycosylated and non-glycosylated CRES isoforms in nonyl phenoxylpolyethoxylethanol (NP40) extracts of the caput, but not cauda, sperm. Immunohistochemical analysis of the caput and cauda epithelium showed that CRES is secreted by the Golgi apparatus of the ii initial segment, fills the proximal caput lumen, and disappears by mid caput. Western blots of caput and cauda tissue and luminal fluid revealed 14 and 19 kDa immunoreactive bands in caput tissues and luminal fluid, but not in the cauda. This study concludes that there are two origins of CRES, one arising in the testis and the other in the epididymis. Testicular CRES is ionically and covalently associated with the ODF while epididymal CRES is detergent soluble and is most likely associated temporarily with the surface of caput epididymal sperm.

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The notion that each state in the international system approaches matters of war and peace somewhat differently because they each possess a unique strategic culture is not a new or obscure one – but it nevertheless remains controversial. While some scholars dismiss the utility or practicality of examining states’ cultures when seeking to explain or predict those states’ patterns of strategic decision-making, even amongst those who accept that we should pay attention to cultural differences between states when carrying out strategic analysis there remains a frustratingly eclectic range of offerings from scholars regarding how best to do so. In short, significant uncertainty remains regarding both whether strategic culture should be used as an analytical tool and, if it is so utilized, how one should go about doing so. This thesis therefore explores the concept of strategic culture in great detail, both theoretical and empirical. The opening three chapters examine why the more traditional rationalist/materialistic theories should not exclusively dominate strategic analysis, then the various existing strategic cultural offerings are considered and critiqued and, finally, a new conceptual model for strategic cultural analysis is proposed which draws from the hitherto largely neglected psychological and sociological literature. Both of these fields, it is submitted in Chapter 3, have spent more time and effort developing ways of understanding and analyzing culture than the field of IR has to date, and therefore the models and methods debated and developed in these fields should, it is argued, be ‘imported’ into IR to drive further strategic cultural research. The thesis then moves in the following six chapters to consider Australia’s strategic culture. The purpose of this part of the thesis is two-fold: first, it illustrates how the model offered in Chapter 3 works and, by implication, suggests how scholars may go about applying it to other cases. Second, and perhaps more importantly, the latter six chapters explore the twists and turns of Australia’s substantive strategic decision-making over the course of the last century or more, thereby explaining how Australia’s strategic history can be understood from a cultural perspective.