2,851 research outputs found
Inducer dynamics full-flow, full-admission hydraulic turbine drive Interim report for tasks 1, 2, and 3
Hydrodynamical and mechanical design layout for two-speed hydraulic turbine inducer, computer simulation of pumping system and test facility performance, and study of demonstration uni
Geometric View of Measurement Errors
The slope of the best fit line from minimizing the sum of the squared oblique
errors is the root of a polynomial of degree four. This geometric view of
measurement errors is used to give insight into the performance of various
slope estimators for the measurement error model including an adjusted fourth
moment estimator introduced by Gillard and Iles (2005) to remove the jump
discontinuity in the estimator of Copas (1972). The polynomial of degree four
is associated with a minimun deviation estimator. A simulation study compares
these estimators showing improvement in bias and mean squared error
Overeducation across British regions
This paper analyses levels of over-education and wage returns to education for males across
eleven regions of the UK using Labour Force Survey data. Significant differences are found
in the probability of being over-educated across regions; also, differences are found in the
return to the âcorrectâ level of education in each region, in each case associated with
flexibility of movement between and into particular regions, which determines the ease of job
matching. Furthermore, evidence is found that, after controlling for the level of education
acquired, there exists a premium to the âcorrectâ level of education, which varies across UK
regions
Spontaneous CP Violation at the Electroweak Scale
Utilizing results on the cosmology of anomalous discrete symmetries we show
that models of spontaneous CP violation can in principle avoid the domain wall
problem first pointed out by Zel'dovich, Kobzarev and Okun. A small but nonzero
explicitly breaks CP and can lift the degeneracy of the two CP
conjugate vacua through nonperturbative effects so that the domain walls become
unstable, but survive to cosmologically interesting epochs. We explore the
viability of spontaneous CP violation in the context of two Higgs models, and
find that the invisible axion solution of the strong CP problem cannot be
implemented without further extensions of the Higgs sector.Comment: 10 page
Effects of alteplase for acute stroke on the distribution of functional outcomes: a pooled analysis of 9 trials
BackgroundâThrombolytic therapy with intravenous alteplase within 4.5 hours of ischemic stroke onset increases the overall likelihood of an excellent outcome (no, or nondisabling, symptoms). Any improvement in functional outcome distribution has value, and herein we provide an assessment of the effect of alteplase on the distribution of the functional level by treatment delay, age, and stroke severity.
MethodsâPrespecified pooled analysis of 6756 patients from 9 randomized trials comparing alteplase versus placebo/open control. Ordinal logistic regression models assessed treatment differences after adjustment for treatment delay, age, stroke severity, and relevant interaction term(s).
ResultsâTreatment with alteplase was beneficial for a delay in treatment extending to 4.5 hours after stroke onset, with a greater benefit with earlier treatment. Neither age nor stroke severity significantly influenced the slope of the relationship between benefit and time to treatment initiation. For the observed case mix of patients treated within 4.5 hours of stroke onset (mean 3 hours and 20 minutes), the net absolute benefit from alteplase (ie, the difference between those who would do better if given alteplase and those who would do worse) was 55 patients per 1000 treated (95% confidence interval, 13â91; P=0.004).
ConclusionsâTreatment with intravenous alteplase initiated within 4.5 hours of stroke onset increases the chance of achieving an improved level of function for all patients across the age spectrum, including the over 80s and across all severities of stroke studied (top versus bottom fifth means: 22 versus 4); the earlier that treatment is initiated, the greater the benefit
Mapping urban green infrastructure : a novel landscape-based approach to incorporating land-use and land-cover in the mapping of human-dominated systems
Common approaches to mapping green infrastructure in urbanized landscapes invariably focus on measures of land-use or land-cover and associated functional or physical traits. However, such one-dimensional perspectives do not accurately capture the character and complexity of the landscapes in which urban inhabitants live. The new approach presented in this paper demonstrates how open-source, high spatial and temporal resolution data with global coverage can be used to measure and represent the landscape qualities of urban environments. Through going beyond simple metrics of quantity, such as percentage green and blue cover it is now possible to explore the extent to which landscape quality helps to unpick the mixed evidence presented in the literature on the benefits of urban nature to human well-being. Here we present a landscape approach, employing remote sensing, GIS and data reduction techniques, to map urban green infrastructure elements in a large UK city-region. Comparison with existing urban datasets demonstrates considerable improvement in terms of coverage and thematic detail. The characterisation of landscapes, using census tracts as spatial units, and subsequent exploration of associations with social-ecological attributes highlights the further detail which can be uncovered with the approach. For example, eight urban landscape types identified for the case study city exhibited associations with distinct socio-economic conditions accountable not only to quantities but also qualities of green and blue space. The identification of individual landscape features through simultaneous measures of land-use and land cover demonstrated unique and significant associations between the former and indicators of human health and ecological condition. The approach may therefore provide a promising basis for developing further insight into the processes and characteristics which affect human health and wellbeing in urban areas, both in the UK and beyond
Black hole production in tachyonic preheating
We present fully non-linear simulations of a self-interacting scalar field in
the early universe undergoing tachyonic preheating. We find that density
perturbations on sub-horizon scales which are amplified by tachyonic
instability maintain long range correlations even during the succeeding
parametric resonance, in contrast to the standard models of preheating
dominated by parametric resonance. As a result the final spectrum exhibits
memory and is not universal in shape. We find that throughout the subsequent
era of parametric resonance the equation of state of the universe is almost
dust-like, hence the Jeans wavelength is much smaller than the horizon scale.
If our 2D simulations are accurate reflections of the situation in 3D, then
there are wide regions of parameter space ruled out by over-production of black
holes. It is likely however that realistic parameter values, consistent with
COBE/WMAP normalisation, are safetly outside this black hole over-production
region.Comment: 6pages, 7figures, figures correcte
HCI in the Wild MĂȘlĂ©e of Office Life:Explorations in Breaching the PC Data Store
âHCI in the wildâ was meant to be a call to get HCI investigations out of the lab into the mĂȘlĂ©e of real life. This is of course a commendable suggestion, though begs questions about what kinds of methods and topics are suited for exploring in this mĂȘlĂ©e as against in the lab. Claims by some experimentalists that they seek ecological validity in lab studies are largely missing the point since the thing that studies in the wild seek are essentially only those things that occur outside the labâand hence are not things that can be replicated, modelled, or emulated. But in any case, some of those who have taken up the call for studies in the wild have taken this rather too literallyâthey have sought wild places, places where HCI researchers have not gone before. Needless to say this being HCI, the places in question are not often that wild, woods near Brighton, for example, street life in south Cambridge. What they ignore as they venture into these settings is the mĂȘlĂ©e of office life, the place where the bulk of computer systems are located and the place in which, oddly enough, increasingly little HCI research gets done
Barriers for highly qualified A8 immigrants in the UK labour market
The number of migrants arriving in the UK from the EU accession countries has been higher than projected. The evidence indicates that they have been over-represented in low-paid and low-skilled jobs. This is arguably transitory and there should be good prospects of upward mobility. Over-qualification among A8 migrants, measured using the Annual Population Survey data, is examined in this article. The findings show that A8 migrants have been subject to migration penalties at the high end of the UK labour market. There are persistent labour market disadvantages for A8 migrants in the UK and their over-qualification may be a long-term concern
Geriatric pharmacotherapy : optimisation through integrated approach in the hospital setting
Since older patients are more vulnerable to adverse drug-related events, there is a need to ensure appropriate prescribing in these patients in order to prevent misuse, overuse and underuse of drugs. Different tools and strategies have been developed to reduce inappropriate prescribing; the available measures can be divided into medication assessment tools, and speciïŹc interventions to reduce inappropriate prescribing. Implicit criteria of inappropriate prescribing focus on appropriate dosing, search for drug-drug interactions, and increase adherence. Explicit criteria are consensus-based standards focusing on drugs and diseases and include lists of drugs to avoid in general or lists combining drugs with clinical data. These criteria take into consideration differences between patients, and stand for a medication review, by using a systematic approach. Different types of interventions exist in order to reduce inappropriate prescribing in older patients, such as: educational interventions, computerized decision support systems, pharmacist-based interventions, and geriatric assessment. The effects of these interventions have been studied, sometimes in a multifaceted approach combining different techniques, and all types seem to have positive effects on appropriateness of prescribing. Interdisciplinary teamwork within the integrative pharmaceutical care is important for improving of outcomes and safety of drug therapy. The pharmaceutical care process consists offour steps, which are cyclic for an individual patient. These steps are pharmaceutical anamnesis, medication review, design and follow-up of a pharmaceutical care plan. A standardized approach is necessary for the adequate detection and evaluation of drug-related problems. Furthermore, it is clear that drug therapy should be reviewed in-depth, by having full access to medical records, laboratory values and nursing notes. Although clinical pharmacists perform the pharmaceutical care process to manage the patientâs drug therapy in every day clinical practice, the physician takes the ultimate responsibility for the care of the patient in close collaboration with nurses
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