75 research outputs found
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Exploring strategies for coupled 4D-Var data assimilation using an idealised atmosphere-ocean model
Operational forecasting centres are currently developing data assimilation systems for coupled atmosphere-ocean models. Strongly coupled assimilation, in which a single assimilation system is applied to a coupled model, presents significant technical and scientific challenges. Hence weakly coupled assimilation systems are being developed as a first step, in which the coupled model is used to compare the current state estimate with observations, but corrections to the atmosphere and ocean initial conditions are then calculated independently. In this paper we provide a comprehensive description of the different coupled assimilation methodologies in the context of four dimensional variational assimilation (4D-Var) and use an idealised framework to assess the expected benefits of moving towards coupled data assimilation.
We implement an incremental 4D-Var system within an idealised single column atmosphere-ocean model. The system has the capability to run both strongly and weakly coupled assimilations as well as uncoupled atmosphere or ocean only assimilations, thus allowing a systematic comparison of the different strategies for treating the coupled data assimilation problem. We present results from a series of identical twin experiments devised to investigate the behaviour and sensitivities of the different approaches. Overall, our study demonstrates the potential benefits that may be expected from coupled data assimilation. When compared to uncoupled initialisation, coupled assimilation is able to produce more balanced initial analysis fields, thus reducing initialisation shock and its impact on the subsequent forecast. Single observation experiments demonstrate how coupled assimilation systems are able to pass information between the atmosphere and ocean and therefore use near-surface data to greater effect. We show that much of this benefit may also be gained from a weakly coupled assimilation system, but that this can be sensitive to the parameters used in the assimilation
Progress and Challenges in Short to Medium Range Coupled Prediction
The availability of GODAE Oceanview-type ocean forecast systems provides the opportunity to develop high-resolution, short- to medium-range coupled prediction systems. Several groups have undertaken the first experiments based on relatively unsophisticated approaches. Progress is being driven at the institutional level targeting a range of applications that represent their respective national interests with clear overlaps and opportunities for information exchange and collaboration. These include general circulation, hurricanes, extra-tropical storms, high-latitude weather and sea-ice forecasting as well as coastal air-sea interaction. In some cases, research has moved beyond case and sensitivity studies to controlled experiments to obtain statistically significant metrics
Social presence and dishonesty in retail
Self-service checkouts (SCOs) in retail can benefit consumers and retailers, providing control and autonomy to shoppers independent from staff, together with reduced queuing times. Recent research indicates that the absence of staff may provide the opportunity for consumers to behave dishonestly, consistent with a perceived lack of social presence. This study examined whether a social presence in the form of various instantiations of embodied, visual, humanlike SCO interface agents had an effect on opportunistic behaviour. Using a simulated SCO scenario, participants experienced various dilemmas in which they could financially benefit themselves undeservedly. We hypothesised that a humanlike social presence integrated within the checkout screen would receive more attention and result in fewer instances of dishonesty compared to a less humanlike agent. This was partially supported by the results. The findings contribute to the theoretical framework in social presence research. We concluded that companies adopting self-service technology may consider the implementation of social presence in technology applications to support ethical consumer behaviour, but that more research is required to explore the mixed findings in the current study.<br/
Observational needs for improving ocean and coupled reanalysis, S2S prediction, and decadal prediction
Developments in observing system technologies and ocean data assimilation (DA) are symbiotic. New observation types lead to new DA methods and new DA methods, such as coupled DA, can change the value of existing observations or indicate where new observations can have greater utility for monitoring and prediction. Practitioners of DA are encouraged to make better use of observations that are already available, for example, taking advantage of strongly coupled DA so that ocean observations can be used to improve atmospheric analyses and vice versa. Ocean reanalyses are useful for the analysis of climate as well as the initialization of operational long-range prediction models. There are many remaining challenges for ocean reanalyses due to biases and abrupt changes in the ocean-observing system throughout its history, the presence of biases and drifts in models, and the simplifying assumptions made in DA solution methods. From a governance point of view, more support is needed to bring the ocean-observing and DA communities together. For prediction applications, there is wide agreement that protocols are needed for rapid communication of ocean-observing data on numerical weather prediction (NWP) timescales. There is potential for new observation types to enhance the observing system by supporting prediction on multiple timescales, ranging from the typical timescale of NWP, covering hours to weeks, out to multiple decades. Better communication between DA and observation communities is encouraged in order to allow operational prediction centers the ability to provide guidance for the design of a sustained and adaptive observing network
Effectiveness and tolerability of 12-Month Brivaracetam in the real world: EXPERIENCE, an international pooled analysis of individual patient records
Background and Objective
Real-world evidence studies of brivaracetam (BRV) have been restricted in scope, location, and patient numbers. The objective of this pooled analysis was to assess effectiveness and tolerability of brivaracetam (BRV) in routine practice in a large international population.
Methods
EXPERIENCE/EPD332 was a pooled analysis of individual patient records from multiple independent non-interventional studies of patients with epilepsy initiating BRV in Australia, Europe, and the United States. Eligible study cohorts were identified via a literature review and engagement with country lead investigators, clinical experts, and local UCB Pharma scientific/medical teams. Included patients initiated BRV no earlier than January 2016 and no later than December 2019, and had ≥ 6 months of follow-up data. The databases for each cohort were reformatted and standardised to ensure information collected was consistent. Outcomes included ≥ 50% reduction from baseline in seizure frequency, seizure freedom (no seizures within 3 months before timepoint), continuous seizure freedom (no seizures from baseline), BRV discontinuation, and treatment-emergent adverse events (TEAEs) at 3, 6, and 12 months. Patients with missing data after BRV discontinuation were considered non-responders/not seizure free. Analyses were performed for all adult patients (≥ 16 years), and for subgroups by seizure type recorded at baseline; by number of prior antiseizure medications (ASMs) at index; by use of BRV as monotherapy versus polytherapy at index; for patients who switched from levetiracetam to BRV versus patients who switched from other ASMs to BRV; and for patients with focal-onset seizures and a BRV dose of ≤ 200 mg/day used as add-on at index. Analysis populations included the full analysis set (FAS; all patients who received at least one BRV dose and had seizure type and age documented at baseline) and the modified FAS (all FAS patients who had at least one seizure recorded during baseline). The FAS was used for all outcomes other than ≥ 50% seizure reduction. All outcomes were summarised using descriptive statistics.
Results
Analyses included 1644 adults. At baseline, 72.0% were 16–49 years of age and 92.2% had focal-onset seizures. Patients had a median (Q1, Q3) of 5.0 (2.0, 8.0) prior antiseizure medications at index. At 3, 6, and 12 months, respectively, ≥ 50% seizure reduction was achieved by 32.1% (n = 619), 36.7% (n = 867), and 36.9% (n = 822) of patients; seizure freedom rates were 22.4% (n = 923), 17.9% (n = 1165), and 14.9% (n = 1111); and continuous seizure freedom rates were 22.4% (n = 923), 15.7% (n = 1165), and 11.7% (n = 1111). During the whole study follow-up, 551/1639 (33.6%) patients discontinued BRV. TEAEs since prior visit were reported in 25.6% (n = 1542), 14.2% (n = 1376), and 9.3% (n = 1232) of patients at 3, 6, and 12 months, respectively.
Conclusions
This pooled analysis using data from a variety of real-world settings suggests BRV is effective and well tolerated in routine clinical practice in a highly drug-resistant patient population
Pentalogy of Cantrell: two patients and a review to determine prognostic factors for optimal approach
Two patients with incomplete pentalogy of Cantrell are described. The first was a girl with a large omphalocele with evisceration of the heart, liver and intestines with an intact sternum. Echocardiography showed profound intracardiac defects. The girl died 33 h after birth. The second patient was a female fetus with ectopia cordis (EC) without intracardiac anomalies; a large omphalocele with evisceration of the heart, stomach, spleen and liver; a hypoplastic sternum and rib cage; and a scoliosis. The pregnancy was terminated. A review of patients described in the literature is presented with the intention of finding prognostic factors for an optimal approach to patients with the pentalogy of Cantrell. In conclusion the prognosis seems to be poorer in patients with the complete form of pentalogy of Cantrell, EC, and patients with associated anomalies. Intracardial defects do not seem to be a prognostic factor
Assessing recent trends in high-latitude Southern Hemisphere surface climate
Understanding the causes of recent climatic trends and variability in the high-latitude Southern Hemisphere is hampered by a short instrumental record. Here, we analyse recent atmosphere, surface ocean and sea-ice observations in this region and assess their trends in the context of palaeoclimate records and climate model simulations. Over the 36-year satellite era, significant linear trends in annual mean sea-ice extent, surface temperature and sea-level pressure are superimposed on large interannual to decadal variability. However, most observed trends are not unusual when compared with Antarctic paleoclimate records of the past two centuries. With the exception of the positive trend in the Southern Annular Mode, climate model simulations that include anthropogenic forcing are not compatible with the observed trends. This suggests that natural variability likely overwhelms the forced response in the observations, but the models may not fully represent this natural variability or may overestimate the magnitude of the forced response
Brief Assessment of Schizotypal Traits: A Multinational Study
The Schizotypal Personality Questionnaire-Brief (SPQ-B) was
developed with the aim of examining variations in healthy trait
schizotypy, as well as latent vulnerability to psychotic-spectrum
disorders. No previous study has studied the cross-cultural validity of
the SPQ-B in a large cross-national sample. The main goal of the present
study was to analyze the reliability and the internal structure of SPQ-B
scores in a multinational sample of 28,426 participants recruited from 14
countries. The mean age was 22.63 years (SD = 7.08; range 16-68 years),
37.7% (n = 10,711) were men. The omega coefficients were high, ranging
from 0.86 to 0.92 for the total sample. Confirmatory factor analysis
revealed that SPQ-B items were grouped either in a theoretical structure
of three first-order factors (Cognitive-Perceptual, Interpersonal, and
Disorganized) or in a bifactor model (three first-order factors plus a
general factor of schizotypal personality). In addition, the results
supported configural but not strong measurement invariance of SPQ-B
scores across samples. These findings provide new information about the
factor structure of schizotypal personality, and support the validity and
utility of the SPQ-B, a brief and easy tool for assessing self-reported
schizotypal traits, in cross-national research. Theoretical and clinical
implications for diagnostic systems, psychosis models, and cross-national
mental health strategies are derived from these results
Simultaneous perception of phosphenes generated by direct stimulation of a human optic nerve
info:eu-repo/semantics/publishe
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