964 resultados para ddc: 500


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During the Mid-Pleistocene Transition (MPT), the dominant glacial-interglacial cyclicity as inferred from the marine d18O records of benthic foraminifera (d18Obenthic) changed from 41 kyr to 100 kyr years in the absence of a comparable change in orbital forcing. Currently, only two Mg/Ca-derived, high-resolution bottom water temperature (BWT) records exist that can be used with d18Obenthic records to separate temperature and ice volume signals over the Pleistocene. However, these two BWT records suggest a different pattern of climate change occurred over the MPT-a record from North Atlantic DSDP Site 607 suggests BWT decreased with no long-term trend in ice volume over the MPT, while South Pacific ODP Site 1123 suggests that BWT has been relatively stable over the last 1.5 Myr but that there was an abrupt increase in ice volume at ~900 kyr. In this paper we attempt to reconcile these two views of climate change across the MPT. Specifically, we investigated the suggestion that the secular BWT trend obtained from Mg/Ca measurements on Cibicidoides wuellerstorfi and Oridorsalis umbonatus species from N. Atlantic Site 607 is biased by the possible influence of D[CO3]2- on Mg/Ca values in these species by generating a low-resolution BWT record using Uvigerina spp., a genus whose Mg/Ca values are not thought to be influenced by D[CO3]2-. We find a long-term BWT cooling of ~2-3°C occurred from 1500 to ~500 kyr in the N. Atlantic, consistent with the previously generated C. wuellerstorfi and O. umbonatus BWT record. We also find that changes in ocean circulation likely influenced d18Obenthic, BWT, and d18Oseawater records across the MPT. N. Atlantic BWT cooling starting at ~1.2 Ma, presumably driven by high-latitude cooling, may have been a necessary precursor to a threshold response in climate-ice sheet behavior at ~900 ka. At that point, a modest increase in ice volume and thermohaline reorganization may have caused enhanced sensitivity to the 100 kyr orbital cycle.

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General note: Title and date provided by Bettye Lane.

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General note: Title and date provided by Bettye Lane.

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General note: Title provided by Bettye Lane

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Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

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Purpose: There are two goals of this study. The first goal of this study is to investigate the feasibility of using classic textural feature extraction in radiotherapy response assessment among a unique cohort of early stage breast cancer patients who received the single-dose preoperative radiotherapy. The second goal of this study is to investigate the clinical feasibility of using classic texture features as potential biomarkers which are supplementary to regional apparent diffusion coefficient in gynecological cancer radiotherapy response assessment.

Methods and Materials: For the breast cancer study, 15 patients with early stage breast cancer were enrolled in this retrospective study. Each patient received a single-fraction radiation treatment, and DWI and DCE-MRI scans were conducted before and after the radiotherapy. DWI scans were acquired using a spin-echo EPI sequence with diffusion weighting factors of b = 0 and b = 500 mm2/s, and the apparent diffusion coefficient (ADC) maps were calculated. DCE-MRI scans were acquired using a T1-weighted 3D SPGR sequence with a temporal resolution of about 1 minute. The contrast agent (CA) was intravenously injected with a 0.1 mmol/kg bodyweight dose at 2 ml/s. Two parameters, volume transfer constant (Ktrans) and kep were analyzed using the two-compartment Tofts pharmacokinetic model. For pharmacokinetic parametric maps and ADC maps, 33 textural features were generated from the clinical target volume (CTV) in a 3D fashion using the classic gray level co-occurrence matrix (GLCOM) and gray level run length matrix (GLRLM). Wilcoxon signed-rank test was used to determine the significance of each texture feature’s change after the radiotherapy. The significance was set to 0.05 with Bonferroni correction.

For the gynecological cancer study, 12 female patients with gynecologic cancer treated with fractionated external beam radiotherapy (EBRT) combined with high dose rate (HDR) intracavitary brachytherapy were studied. Each patient first received EBRT treatment followed by five fractions of HDR treatment. Before EBRT and before each fraction of brachytherapy, Diffusion Weighted MRI (DWI-MRI) and CT scans were acquired. DWI scans were acquired in sagittal plane utilizing a spin-echo echo-planar imaging sequence with weighting factors of b = 500 s/mm2 and b = 1000 s/mm2, one set of images of b = 0 s/mm2 were also acquired. ADC maps were calculated using linear least-square fitting method. Distributed diffusion coefficient (DDC) maps and stretching parameter α were calculated. For ADC and DDC maps, 33 classic texture features were generated utilizing the classic gray level run length matrix (GLRLM) and gray level co-occurrence matrix (GLCOM) from high-risk clinical target volume (HR-CTV). Wilcoxon signed-rank statistics test was applied to determine the significance of each feature’s numerical value change after radiotherapy. Significance level was set to 0.05 with multi-comparison correction if applicable.

Results: For the breast cancer study, regarding ADC maps calculated from DWI-MRI, 24 out of 33 CTV features changed significantly after the radiotherapy. For DCE-MRI pharmacokinetic parameters, all 33 CTV features of Ktrans and 33 features of kep changed significantly.

For the gynecological cancer study, regarding ADC maps, 28 out of 33 HR-CTV texture features showed significant changes after the EBRT treatment. 28 out of 33 HR-CTV texture features indicated significant changes after HDR treatments. The texture features that indicated significant changes after HDR treatments are the same as those after EBRT treatment. 28 out of 33 HR-CTV texture features showed significant changes after whole radiotherapy treatment process. The texture features that indicated significant changes for the whole treatment process are the same as those after HDR treatments.

Conclusion: Initial results indicate that certain classic texture features are sensitive to radiation-induced changes. Classic texture features with significant numerical changes can be used in monitoring radiotherapy effect. This might suggest that certain texture features might be used as biomarkers which are supplementary to ADC and DDC for assessment of radiotherapy response in breast cancer and gynecological cancer.

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Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

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During the development of a new treatment space for the UK emergency ambulance participatory observations with front-line clinicians revealed the need for an integrated patient monitoring, communication and navigation system. The research identified the different information touch-points and requirements through modes of use analysis, day-in-the-life study and simulation workshops with clinicians. Emergency scenario and role-play with paramedics identified 5 distinct ambulance modes of use. Information flow diagrams were created and checked by paramedics and digital User Interface (UI) wireframes were developed and evaluated by clinicians during clinical evaluations. Feedback from clinicians defined UI design specification further leading to a final design proposal. This research was a further development from the 2007 EPSRC funded “Smart Pods” project. The resulting interactive prototype was co-designed in collaboration with ambulance crews and provides a vision of what could be achieved by integrating well-proven IT technologies and protocols into a package relevant in the emergency medicine field. The system has been reviewed by over 40 ambulance crews and is part of a newly co-designed ambulance treatment space.

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Die kirchliche Verfassungsgeschichte des Mittelalters war von einer analogen Entwicklung scheinbar konträrer monarchischer und kollegialer Prinzipien geprägt. Dem Leitungsanspruch von Äbten, Bischöfen und Päpsten standen Beratungsrechte und Mitbestimmungsanliegen ihrer Mönche, Domkapitulare und Kardinäle gegenüber. Die Abhandlung zeigt auf, wie sich letztere im Verlauf der mittelalterlichen Geschichte als mehr oder weniger unabhängige Wahl- und Ratskollegien formierten und um eine Transformation eher unverbindlicher Beratungsfunktionen zu quasi parlamentarischen Rechten bemühten. Einschlägige verfassungsgeschichtliche Dokumente von der Benediktsregel aus dem 6. Jahrhundert bis hin zu bischöflichen und päpstlichen Wahlkapitulationen aus dem 15. Jahrhundert werden hinsichtlich ihrer kulturgeschichtlichen Zusammenhänge und Wirkungen analysiert.

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El presente estudio se realizó en la finca Santa Rosa de la Universidad Nacional Agraria (UNA), con la finalidad de evaluar la productividad de pollos de engorde línea Cobb 500 , bajo dos sistemas de manejo (estabulados y con acceso a pastoreo) . Para dicho estudio se utilizaron 150 pollos de engorde en total , con un peso inicial promedio de 46 gramos, los cuales fueron d istribuidos mediante un Diseño C ompleta mente al A zar (DCA), en dos tratamientos. Los tratamientos evaluados fueron: T1 pollos estabulados alimentados con concentrado comercial, T2 pollos alimentados con concentrado comercial pero con acceso al pastoreo (8 horas/día) . Las variables evaluadas fueron: ganancia media diaria (GMD), peso promedio semanal (PPS), índice de conversión alimenticia (ICA), índice de eficiencia (I E), peso de la canal (PC), e índice de mortalidad (IM). Para el análisis estadístico se utilizó un DCA y prueba de separación de medias por el método de Tukey, mediante el paquete estadístico Infostat . No se encontraron diferencias significativas (p>0.05) para C onsumo de alimento , GMD, ICA, RC y IE; Existiendo diferencias significativas (p > 0.05) para PPS , donde el T1 (2796 g) s uperó al T2 (2574 g) y para PC el T1 (2059.86 g) superó al T2 (1855.78 g). En conclusión podemos afirmar que los pollos de engorde bajo un manejo con acceso a pastoreo, son productivamente más eficientes que los pollos estabulados.

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Mestrado em Contabilidade e Análise Financeira,

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Collagen is the most abundant protein in the animal kingdom. It is of fundamental importance during development for cell differentiation and tissue morphogenesis as well as in pathological processes such as fibrosis and cancer cell migration. However, our understanding of the mechanisms of procollagen secretion remains limited. Here, we show that TFG organizes transitional ER (tER) and ER exit sites (ERESs) into larger structures. Depletion of TFG results in dispersion of tER elements that remain associated with individual ER-Golgi intermediate compartments (ERGICs) as largely functional ERESs. We show that TFG is not required for the transport and packaging of small soluble cargoes but is necessary for the export of procollagen from the ER. Our work therefore suggests a key relationship between the structure and function of ERESs and a central role for TFG in optimizing COPII assembly for procollagen export.

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Shows stages and operations undertaken in revising the New Jersey state base map.