916 resultados para transmission of data and images
Resumo:
When studying heterogeneous aquifer systems, especially at regional scale, a degree of generalization is anticipated. This can be due to sparse sampling regimes, complex depositional environments or lack of accessibility to measure the subsurface. This can lead to an inaccurate conceptualization which can be detrimental when applied to groundwater flow models. It is important that numerical models are based on observed and accurate geological information and do not rely on the distribution of artificial aquifer properties. This can still be problematic as data will be modelled at a different scale to which it was collected. It is proposed here that integrating geophysics and upscaling techniques can assist in a more realistic and deterministic groundwater flow model. In this study, the sedimentary aquifer of the Lagan Valley in Northern Ireland is chosen due to intruding sub-vertical dolerite dykes. These dykes are of a lower permeability than the sandstone aquifer. The use of airborne magnetics allows the delineation of heterogeneities, confirmed by field analysis. Permeability measured at the field scale is then upscaled to different levels using a correlation with the geophysical data, creating equivalent parameters that can be directly imported into numerical groundwater flow models. These parameters include directional equivalent permeabilities and anisotropy. Several stages of upscaling are modelled in finite element. Initial modelling is providing promising results, especially at the intermediate scale, suggesting an accurate distribution of aquifer properties. This deterministic based methodology is being expanded to include stochastic methods of obtaining heterogeneity location based on airborne geophysical data. This is through the Direct Sample method of Multiple-Point Statistics (MPS). This method uses the magnetics as a training image to computationally determine a probabilistic occurrence of heterogeneity. There is also a need to apply the method to alternate geological contexts where the heterogeneity is of a higher permeability than the host rock.
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This article addresses the lack of work on media and crime in Critical Discourse Analysis (CDA), using an example of a factual television crime report. The existing research in media studies and criminology points to the way that the media misrepresents crime by distorting public understandings and backgrounding structural issues, such as poverty, which are related to crime thereby legitimising a criminal justice system that serves the interests of the powerful in society. Using social actor and transitivity analysis, this article shows how multimodal CDA can make an important contribution as it reveals the more subtle linguistic strategies and visual representations by which this process is accomplished, showing how each plays a part in the recontextualisation of social practice. This programme backgrounds which crimes are committed but foregrounds mental states and the neutrality of policing.
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Funded by the Economic and Social Research Council this partnership project between the Childhood, Transition and Social Justice Initiative at Queen’s University and Include Youth focuses on the negative stereotyping of children and young people and the role and responsibilities of the media in the creation and transmission of negative images. Engaging with children, young people, organisations working with children and young people and media representatives, the project uses research evidence to explore negative media representation and its consequences for children’s rights, public reaction and policy initiatives in Northern Ireland. This report represents a summary of the findings of engagement with 141 children and young people. It outlines how they feel they are presented by the media and the impacts of this. It concludes by noting ways forward in challenging negative portrayals.
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OBJECTIVE: To investigate the impact of smoking and smoking cessation on cardiovascular mortality, acute coronary events, and stroke events in people aged 60 and older, and to calculate and report risk advancement periods for cardiovascular mortality in addition to traditional epidemiological relative risk measures.
DESIGN: Individual participant meta-analysis using data from 25 cohorts participating in the CHANCES consortium. Data were harmonised, analysed separately employing Cox proportional hazard regression models, and combined by meta-analysis.
RESULTS: Overall, 503,905 participants aged 60 and older were included in this study, of whom 37,952 died from cardiovascular disease. Random effects meta-analysis of the association of smoking status with cardiovascular mortality yielded a summary hazard ratio of 2.07 (95% CI 1.82 to 2.36) for current smokers and 1.37 (1.25 to 1.49) for former smokers compared with never smokers. Corresponding summary estimates for risk advancement periods were 5.50 years (4.25 to 6.75) for current smokers and 2.16 years (1.38 to 2.39) for former smokers. The excess risk in smokers increased with cigarette consumption in a dose-response manner, and decreased continuously with time since smoking cessation in former smokers. Relative risk estimates for acute coronary events and for stroke events were somewhat lower than for cardiovascular mortality, but patterns were similar.
CONCLUSIONS: Our study corroborates and expands evidence from previous studies in showing that smoking is a strong independent risk factor of cardiovascular events and mortality even at older age, advancing cardiovascular mortality by more than five years, and demonstrating that smoking cessation in these age groups is still beneficial in reducing the excess risk.
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Background: Nursing homes for older people provide an environment likely to promote the acquisition and spread of meticillin-resistant Staphylococcus aureus (MRSA), putting residents at increased risk of colonisation and infection. It is recognised that infection prevention and control strategies are important in preventing and controlling MRSA transmission.
Objectives: To determine the effects of infection prevention and control strategies for preventing the transmission of MRSA in nursing homes for older people.
Search methods: In August 2013, for this third update, we searched the Cochrane Wounds Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), Database of Abstracts of Reviews of Effects (DARE, The Cochrane Library), Ovid MEDLINE, OVID MEDLINE (In-process and Other Non-Indexed Citations), Ovid EMBASE, EBSCO CINAHL, Web of Science and the Health Technology Assessment (HTA) website. Research in progress was sought through Current Clinical Trials, Gateway to Reseach, and HSRProj (Health Services Research Projects in Progress).
Selection criteria: All randomised and controlled clinical trials, controlled before and after studies and interrupted time series studies of infection prevention and control interventions in nursing homes for older people were eligible for inclusion.
Data collection and analysis: Two review authors independently reviewed the results of the searches. Another review author appraised identified papers and undertook data extraction which was checked by a second review author.
Main results: For this third update only one study was identified, therefore it was not possible to undertake a meta-analysis. A cluster randomised controlled trial in 32 nursing homes evaluated the effect of an infection control education and training programme on MRSA prevalence. The primary outcome was MRSA prevalence in residents and staff, and a change in infection control audit scores which measured adherence to infection control standards. At the end of the 12 month study, there was no change in MRSA prevalence between intervention and control sites, while mean infection control audit scores were significantly higher in the intervention homes compared with control homes.
Authors' conclusions: There is a lack of research evaluating the effects on MRSA transmission of infection prevention and control strategies in nursing homes. Rigorous studies should be conducted in nursing homes, involving residents and staff to test interventions that have been specifically designed for this unique environment.
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Freshwater reservoir effects (FRE) can cause a major problem with radiocarbon dating human skeletal material in the Eurasian steppe. Recent research has demonstrated that, for the Eneolithic to Early Bronze Age sites of North-Eastern Kazakhstan, the maximum fish-herbivore freshwater reservoir offset observed equals 301±47 14C yrs, as such indicating that 14C dates from aquatic and human samples from the area apparently need to be interpreted with caution as they are likely to be affected by the offset. The current paper presents the new data on the FRE of the Eneolithic to the Early Iron Age sites of Kazakhstan and South of Siberia.
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Background: Long working hours might increase the risk of cardiovascular disease, but prospective evidence is scarce, imprecise, and mostly limited to coronary heart disease. We aimed to assess long working hours as a risk factor for incident coronary heart disease and stroke.
Methods We identified published studies through a systematic review of PubMed and Embase from inception to Aug 20, 2014. We obtained unpublished data for 20 cohort studies from the Individual-Participant-Data Meta-analysis in Working Populations (IPD-Work) Consortium and open-access data archives. We used cumulative random-effects meta-analysis to combine effect estimates from published and unpublished data.
Findings We included 25 studies from 24 cohorts in Europe, the USA, and Australia. The meta-analysis of coronary heart disease comprised data for 603 838 men and women who were free from coronary heart disease at baseline; the meta-analysis of stroke comprised data for 528 908 men and women who were free from stroke at baseline. Follow-up for coronary heart disease was 5·1 million person-years (mean 8·5 years), in which 4768 events were recorded, and for stroke was 3·8 million person-years (mean 7·2 years), in which 1722 events were recorded. In cumulative meta-analysis adjusted for age, sex, and socioeconomic status, compared with standard hours (35-40 h per week), working long hours (≥55 h per week) was associated with an increase in risk of incident coronary heart disease (relative risk [RR] 1·13, 95% CI 1·02-1·26; p=0·02) and incident stroke (1·33, 1·11-1·61; p=0·002). The excess risk of stroke remained unchanged in analyses that addressed reverse causation, multivariable adjustments for other risk factors, and different methods of stroke ascertainment (range of RR estimates 1·30-1·42). We recorded a dose-response association for stroke, with RR estimates of 1·10 (95% CI 0·94-1·28; p=0·24) for 41-48 working hours, 1·27 (1·03-1·56; p=0·03) for 49-54 working hours, and 1·33 (1·11-1·61; p=0·002) for 55 working hours or more per week compared with standard working hours (ptrend<0·0001).
Interpretation Employees who work long hours have a higher risk of stroke than those working standard hours; the association with coronary heart disease is weaker. These findings suggest that more attention should be paid to the management of vascular risk factors in individuals who work long hours.
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ThetimingofNeanderthal disappearanceandtheextent to whichthey overlapped with the earliest incoming anatomically modern humans (AMHs)inEurasia arekey questions inpalaeoanthropology1,2 .Deter- mining the spatiotemporal relationship between the two populations is crucial if we are to understand the processes, timing and reasons leading to the disappearance of Neanderthals and the likelihood of cultural and genetic exchange. Serious technical challenges, however, havehinderedreliable datingof the period,as theradiocarbonmethod reaches its limit at 50,000 years ago3 .Herewe apply improved accel- erator mass spectrometry 14C techniques to construct robust chro- nologies from 40 key Mousterian and Neanderthal archaeological sites, ranging fromRussia toSpain.Bayesianagemodellingwas used togenerate probability distributionfunctions todetermine the latest appearancedate.Weshowthat theMousterianendedby41,030–39,260 calibratedyears BP(at95.4%probability) acrossEurope.Wealsodem- onstrate that succeeding ‘transitional’ archaeological industries, one ofwhich has beenlinked withNeanderthals (Cha ˆtelperronian)4 ,end at a similar time. Our data indicate that the disappearance of Nean- derthals occurred at different times in different regions.Comparing the data with results obtained fromthe earliest datedAMHsites in Europe, associated with the Uluzzian technocomplex5 , allows us to quantify the temporal overlap between the two human groups. The results revealasignificantoverlap of 2,600–5,400years (at 95.4%prob- ability).This hasimportant implications formodels seeking toexplain the cultural, technological and biological elements involved in the replacement of Neanderthals byAMHs.Amosaic of populations in Europe during the Middle to Upper Palaeolithic transition suggests that there was ample time for the transmission of cultural and sym- bolic behaviours, as well as possible genetic exchanges, between the two groups.
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Perfect information is seldom available to man or machines due to uncertainties inherent in real world problems. Uncertainties in geographic information systems (GIS) stem from either vague/ambiguous or imprecise/inaccurate/incomplete information and it is necessary for GIS to develop tools and techniques to manage these uncertainties. There is a widespread agreement in the GIS community that although GIS has the potential to support a wide range of spatial data analysis problems, this potential is often hindered by the lack of consistency and uniformity. Uncertainties come in many shapes and forms, and processing uncertain spatial data requires a practical taxonomy to aid decision makers in choosing the most suitable data modeling and analysis method. In this paper, we: (1) review important developments in handling uncertainties when working with spatial data and GIS applications; (2) propose a taxonomy of models for dealing with uncertainties in GIS; and (3) identify current challenges and future research directions in spatial data analysis and GIS for managing uncertainties.
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Passive intermodulation (PIM) often limits the performance of communication systems with analog and digitally-modulated signals and especially of systems supporting multiple carriers. Since the origins of the apparently multiple physical sources of nonlinearity causing PIM are not fully understood, the behavioral models are frequently used to describe the process of PIM generation. In this paper a polynomial model of memoryless nonlinearity is deduced from PIM measurements of a microstrip line with distributed nonlinearity with two-tone CW signals. The analytical model of nonlinearity is incorporated in Keysight Technology’s ADS simulator to evaluate the metrics of signal fidelity in the receive band for analog and digitally-modulated signals. PIM-induced distortion and cross-band interference with modulated signals are compared to those with two-tone CW signals. It is shown that conventional metrics can be applied to quantify the effect of distributed nonlinearities on signal fidelity. It is found that the two-tone CW test provides a worst-case estimate of cross-band interference for two-carrier modulated signals whereas with a three-carrier signal PIM interference in the receive band is noticeably overestimated. The simulated constellation diagrams for QPSK signals demonstrate that PIM interference exhibits the distinctive signatures of correlated distortion and this indicates that there are opportunities for mitigating PIM interference and that PIM interference cannot be treated as noise. One of the interesting results is that PIM distortion on a transmission line results in asymmetrical regrowth of output PIM interference for modulated signals.
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Rapid and affordable tumor molecular profiling has led to an explosion of clinical and genomic data poised to enhance the diagnosis, prognostication and treatment of cancer. A critical point has now been reached at which the analysis and storage of annotated clinical and genomic information in unconnected silos will stall the advancement of precision cancer care. Information systems must be harmonized to overcome the multiple technical and logistical barriers to data sharing. Against this backdrop, the Global Alliance for Genomic Health (GA4GH) was established in 2013 to create a common framework that enables responsible, voluntary and secure sharing of clinical and genomic data. This Perspective from the GA4GH Clinical Working Group Cancer Task Team highlights the data-aggregation challenges faced by the field, suggests potential collaborative solutions and describes how GA4GH can catalyze a harmonized data-sharing culture.
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Tese de doutoramento, Ciências Geofísicas e da Geoinformação (Geofisíca), Universidade de Lisboa, Faculdade de Ciências, 2014