809 resultados para Change-over Designs


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Many image processing methods, such as techniques for people re-identification, assume photometric constancy between different images. This study addresses the correction of photometric variations based upon changes in background areas to correct foreground areas. The authors assume a multiple light source model where all light sources can have different colours and will change over time. In training mode, the authors learn per-location relations between foreground and background colour intensities. In correction mode, the authors apply a double linear correction model based on learned relations. This double linear correction includes a dynamic local illumination correction mapping as well as an inter-camera mapping. The authors evaluate their illumination correction by computing the similarity between two images based on the earth mover's distance. The authors compare the results to a representative auto-exposure algorithm found in the recent literature plus a colour correction one based on the inverse-intensity chromaticity. Especially in complex scenarios the authors’ method outperforms these state-of-the-art algorithms.

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Social pressure exerted by urban development, the increase in erosion on many coastal stretches, and the rise in sea level due to climate change over the last few decades have led governments to increase investment in coastal protection. In turn, a reduction in costs and increases in ease of construction and rate of implementation have led to sand-filled geotextile elements, such as bags, tubes, and containers, becoming an alternative or supplement to traditional coastal defence materials, such as rubble mounds, concrete, and so on. Not all coastal zones are appropriate for sand-filled geotextile structures as coastal defences. This article analyses suitable zones for locating geotextile bag revetments to protect coasts from storm erosion and concludes that the least suitable zones are the surf zone (on an open coast and on a slightly protected coast) and deep water (on an open coast), except if a suitable reinforcement is carried out when the demand makes it necessary this build this kind of defence.

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A sensitive, labor-saving, and easily automatable nonradioactive procedure named APEX-FCS (amplified probe extension detected by fluorescence correlation spectroscopy) has been established to detect specific in vitro amplification of pathogen genomic sequences. As an example, Mycobacterium tuberculosis genomic DNA was subjected to PCR amplification with the Stoffel fragment of Thermus aquaticus DNA polymerase in the presence of nanomolar concentrations of a rhodamine-labeled probe (third primer), binding to the target in between the micromolar amplification primers. The probe becomes extended only when specific amplification occurs. Its low concentration avoids false-positives due to unspecific hybridization under PCR conditions. With increasing portion of extended probe molecules, the probe’s average translational diffusion properties gradually change over the course of the reaction, reflecting amplification kinetics. Following PCR, this change from a stage of high to a stage of low mobility can directly be monitored during a 30-s measurement using a fluorescence correlation spectroscopy device. Quantitation down to 10 target molecules in a background of 2.5 μg unspecific DNA without post-PCR probe manipulations could be achieved with different primer/probe combinations. The assay holds the promise to concurrently perform amplification, probe hybridization, and specific detection without opening the reaction chamber, if sealable foils are used.

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In the vertebrate central nervous system, the retina has been a useful model for studies of cell fate determination. Recent results from studies conducted in vitro and in vivo suggest a model of retinal development in which both the progenitor cells and the environment change over time. The model is based upon the notion that the mitotic cells within the retina change in their response properties, or "competence", during development. These changes presage the ordered appearance of distinct cell types during development and appear to be necessary for the production of the distinct cell types. As the response properties of the cells change, so too do the environmental signals that the cells encounter. Together, intrinsic properties and extrinsic cues direct the choice of cell fate.

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Objective: Healthy relationships between adolescents and their caregivers have been robustly associated with better youth outcomes in a variety of domains. Youth in contact with the child welfare system are at higher risk for worse outcomes including mental health problems and home placement instability. A growing body of literature points to youth mental health problems as both a predictor and a consequence of home placement instability in this population; the present study aimed to expand our understanding of these phenomena by examining the interplay among the caregiver-child relationship, youth mental health symptoms, and placement change over time. Method: The sample consisted of 1,179 youths aged 11-16, from the National Survey of Child and Adolescent Well-Being, a nationally representative sample of children in contact with the child welfare system. We used bivariate correlations and autoregressive cross-lagged path analysis to examine how youths’ reports of their externalizing and internalizing symptoms, their relationship with their caregivers, and placement changes reciprocally influenced one another over three time points. Results: In the overall models, early internalizing symptoms significantly negatively predicted the quality of the caregiver-child relationship at the next time point, and early externalizing symptoms predicted subsequent placement change. In addition, later externalizing symptoms negatively predicted subsequent reports of relationship quality, and later placement changes predicted subsequent externalizing problems; these relationships were significant only at the trend level (p < .10). The quality of the relationship was significantly negatively correlated with externalizing and internalizing problems at all time points, and all variables demonstrated autoregressive stability over time. Conclusions: Our findings support the importance of comprehensive interventions for youth in contact with the child welfare system, which target not only youth symptoms in isolation, but also the caregiver-child relationship, as a way to improve social-emotional outcomes in this high-risk population.

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From climate change over peak oil to the geopolitical scramble for the Arctic, there are ample signs that a global energy crisis is unfolding. The sheer scale and urgency of this looming crisis calls for international coordination. Yet, even a cursory look at the existing international energy institutions leads to a sobering conclusion: the global energy governance architecture is weak, fragmented and incomplete. This policy brief discusses both the flaws in the multilateral energy architecture and some emerging ideas to strengthen it, such as the proposal for a Sustainable Energy Trade Agreement and the new American disclosure rules for the extractive sector.

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Sediment cores from the Amazon deep sea fan recovered during R/V Meteor cruise 16-2 show in detail the modern areal distribution of sedimentary organic carbon, stable organic carbon isotopes of the organic matter (OM), as well as variations in the depositional processes. In addition, we studied up to 300 m long drilled sediment records recovered during ODP Leg 155 which allow evaluation of temporal variations on the Amazon fan. Our results reveal new evidence for a very rapid change of fan depositional processes and organic carbon source at times of sea-level change over the middle and lower Amazon fan. To estimate the amount of terrestrial organic carbon stored in sediments from the last glacial in the Amazon fan we used stable organic carbon isotopes of the OM (delta13Corg), organic carbon content (Corg), and age models based on oxygen isotopes, faunal data, and magnetic excursions. Following our results, the organic carbon accumulation on the Amazon deep sea fan is controlled by glacio-eustatic sea-level oscillations. Interglacial sea-level high stand sediments are dominated by marine OM whereas during glacial sea-level low stands terrestrial organic carbon is transported beyond the continental shelf through the Amazon canyon and deposited directly onto the Amazon deep sea fan. Glacial sediments of the Amazon fan stored approximately 73*10**15 g terrestrial Corg in 20,000 years or 3.7*10**12 g terrestrial Corg/yr (equivalent to 7-12% of the riverine organic carbon discharge; assuming constant paleo discharge), which is about the same amount of terrestrial organic carbon as deposited on the Amazon shelf today (3.1*10**12 g terrestrial Corg/yr or 6-10% of the modern riverine organic carbon discharge).

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Thesis (Ph.D.)--University of Washington, 2016-06

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Thesis (Ph.D.)--University of Washington, 2016-06

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An increased incidence of attack has been identified as a major characteristic of the new threat posed by terrorist groups such as al Qaeda. This article considers what such a change means for Western national security systems by examining bow different parts of the system change over time. It becomes evident that Western national security systems are structured on an assumption of comparatively slow state-based threats. In contrast, terrorist franchises operate at a faster pace, are more 'lightweight' and can adapt within the operational and capability cycles of Western governments. Neither network-centric warfare nor an improved assessment of the threat, called for by some, offers a panacea in this regard. Rather, it is clear that not only do Western governments need to adjust their operational and capability cycles, but that they also need a greater diversity of responses to increase overall national security resilience and offer more tools for policy-makers.

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This study aimed to investigate whether fluid shifts alter ciprofloxacin pharmacokinetics in critically ill patients over time. Patients >= 18 years, with normal renal function, requiring intensive care treatment and parenteral antibiotics were enrolled. Group A (22 patients) included patients with documented intra-abdominal infections. Group B (18 patients) included patients with severe sepsis from other causes. All patients received intravenous ciprofloxacin 400 mg every 8 h infused over 60 min. Eight timed blood specimens were taken on days 0, 2 and 7. Ciprofloxacin plasma concentrations were determined using high performance liquid chromatography. There were no significant differences between the pharmacokinetics of the two groups or over time. Ciprofloxacin pharmacokinetics in critically ill patients do not change over time, and intra-abdominal sepsis does not alter ciprofloxacin pharmacokinetic parameters to a greater degree than sepsis from other causes in critically ill patients. (c) 2005 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

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This research used resource allocation theory to generate predictions regarding dynamic relationships between self-efficacy and task performance from 2 levels of analysis and specificity. Participants were given multiple trials of practice on an air traffic control task. Measures of task-specific self-efficacy and performance were taken at repeated intervals. The authors used multilevel analysis to demonstrate differential and dynamic effects. As predicted, task-specific self-efficacy was negatively associated with task performance at the within-person level. On the other hand, average levels of task-specific self-efficacy were positively related to performance at the between-persons level and mediated the effect of general self-efficacy. The key findings from this research relate to dynamic effects - these results show that self-efficacy effects can change over time, but it depends on the level of analysis and specificity at which self-efficacy is conceptualized. These novel findings emphasize the importance of conceptualizing self-efficacy within a multilevel and multispecificity framework and make a significant contribution to understanding the way this construct relates to task performance.

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Background It has been suggested that community treatment orders (CTOs) will prevent readmission to hospital, but controlled studies have been inconclusive. We aimed to test the hypothesis that hospital discharges made subject to CTOs are associated with a reduced risk of readmission. The use of such a measure is likely to change after its introduction as clinicians acquire familiarity with it, and we also tested the hypothesis that the characteristics of patients subject to CTOs changed over time in the first decade of their use in Victoria, Australia. Method A database from Victoria, Australia (total population 4.8 million) was used. Cox proportional hazard models compared the hazard ratios of readmission to hospital before the end of the study period (1992-2000) for 16,216 discharges subject to a CTO and 112,211 not subject to a CTO. Results Community treatment orders used on discharge from a first admission to hospital were associated with a higher risk of readmission, but CTOs following subsequent admissions were associated with lower readmission risk. The risk also declined over the study period. Conclusions The effect of using a CTO depends on the patient's history. At a population level their introduction may not reduce readmission to hospital. Their impact may change over time.

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Onsite wastewater treatment systems aim to assimilate domestic effluent into the environment. Unfortunately failure of such systems is common and inadequate effluent treatment can have serious environmental implications. The capacity of a particular soil to treat wastewater will change over time. The physical properties influence the rate of effluent movement through the soil and its chemical properties dictate the ability to renovate effluent. A research project was undertaken to determine the role that physical and chemical soil properties play in predicting the long-term behaviour of soil under effluent irrigation and to determine if they have a potential function as early indicators of adverse effects of effluent irrigation on treatment sustainability. Principal Component Analysis (PCA) and Cluster Analysis grouped the soils independently of their soil classifications and allowed us to distinguish the most suitable soils for sustainable long term effluent irrigation and determine the most influential soil parameters to characterise them. Multivariate analysis allowed a clear distinction between soils based on the cation exchange capacities. This in turn correlated well with the soil mineralogy. Mixed mineralogy soils in particular sodium or magnesium dominant soils are the most susceptible to dispersion under effluent irrigation. The soil Exchangeable Sodium Percentage (ESP) was identified as a crucial parameter and was highly correlated with percentage clay, electrical conductivity, exchangeable sodium, exchangeable magnesium and low Ca:Mg ratios (less than 0.5).