529 research outputs found
Helping crisis responders find the informative needle in the tweet haystack
Crisis responders are increasingly using social media, data and other digital sources of information to build a situational understanding of a crisis situation in order to design an effective response. However with the increased availability of such data, the challenge of identifying relevant information from it also increases. This paper presents a successful automatic approach to handling this problem. Messages are filtered for informativeness based on a definition of the concept drawn from prior research and crisis response experts. Informative messages are tagged for actionable data -- for example, people in need, threats to rescue efforts, changes in environment, and so on. In all, eight categories of actionability are identified. The two components -- informativeness and actionability classification -- are packaged together as an openly-available tool called Emina (Emergent Informativeness and Actionability)
Improving Fiber Alignment in HARDI by Combining Contextual PDE Flow with Constrained Spherical Deconvolution
We propose two strategies to improve the quality of tractography results
computed from diffusion weighted magnetic resonance imaging (DW-MRI) data. Both
methods are based on the same PDE framework, defined in the coupled space of
positions and orientations, associated with a stochastic process describing the
enhancement of elongated structures while preserving crossing structures. In
the first method we use the enhancement PDE for contextual regularization of a
fiber orientation distribution (FOD) that is obtained on individual voxels from
high angular resolution diffusion imaging (HARDI) data via constrained
spherical deconvolution (CSD). Thereby we improve the FOD as input for
subsequent tractography. Secondly, we introduce the fiber to bundle coherence
(FBC), a measure for quantification of fiber alignment. The FBC is computed
from a tractography result using the same PDE framework and provides a
criterion for removing the spurious fibers. We validate the proposed
combination of CSD and enhancement on phantom data and on human data, acquired
with different scanning protocols. On the phantom data we find that PDE
enhancements improve both local metrics and global metrics of tractography
results, compared to CSD without enhancements. On the human data we show that
the enhancements allow for a better reconstruction of crossing fiber bundles
and they reduce the variability of the tractography output with respect to the
acquisition parameters. Finally, we show that both the enhancement of the FODs
and the use of the FBC measure on the tractography improve the stability with
respect to different stochastic realizations of probabilistic tractography.
This is shown in a clinical application: the reconstruction of the optic
radiation for epilepsy surgery planning
Five-year outcome of clinical recovery and subjective well-being in older Dutch patients with schizophrenia
Outcome of schizophrenia in later life can be evaluated from different perspectives. The recovery concept has moved forward this evaluation, discerning clinical-based and patient-based definitions. Longitudinal data on measures of recovery in older individuals with schizophrenia are scant. This study evaluated the five-year outcome of clinical recovery and subjective well-being in a sample of 73 older Dutch schizophrenia patients (mean age 65.9 years; SD 5.4), employing a catchment-area based design that included both community living and institutionalized patients regardless of the age of onset of their disorder. At baseline (T1), 5.5% of participants qualified for clinical recovery, while at five-year follow-up (T2), this rate was 12.3% (p = 0.18; exact McNemar's test). Subjective well-being was reported by 20.5% of participants at T1 and by 27.4% at T2 (p = 0.27; exact McNemar's test). Concurrence of clinical recovery and subjective well-being was exceptional, being present in only one participant (1.4%) at T1 and in two participants (2.7%) at T2. Clinical recovery and subjective well-being were not correlated neither at T1 (p = 0.82; phi = 0.027) nor at T2 (p = 0.71; phi =-0.044). There was no significant correlation over time between clinical recovery at T1 and subjective well-being at T2 (p = 0.30; phi = 0.122) nor between subjective well-being at T1 and clinical recovery at T2 (p = 0.45; phi =-0.088). These results indicate that while reaching clinical recovery is relatively rare in older individuals with schizophrenia, it is not a prerequisite to experience subjective well-being
Modelling representation errors of atmospheric CO2 mixing ratios at a regional scale
Inverse modelling of carbon sources and sinks requires an accurate quality estimate of the modelling framework to obtain a realistic estimate of the inferred fluxes and their uncertainties. So-called "representation errors" result from our inability to correctly represent point observations with simulated average values of model grid cells. They may add substantial uncertainty to the interpretation of atmospheric CO2 mixing ratio data. We simulated detailed variations in the CO2 mixing ratios with a high resolution (2 km) mesoscale model (RAMS) to estimate the representation errors introduced at larger model grid sizes of 10 100 km. We found that meteorology is the main driver of representation errors in our study causing spatial and temporal variations in the error estimate. Within the nocturnal boundary layer, the representation errors are relatively large and mainly caused by unresolved topography at lower model resolutions. During the day, convective structures, mesoscale circulations, and surface CO2 flux variability were found to be the main sources of representation errors. Interpreting observations near a mesoscale circulation as representative for air with the correct footprint relative to the front can reduce the representation error substantially. The remaining representation error is 0.5 1.5 ppm at 20 100 km resolution
Reproducibility of 3D scanning in the periorbital region
The reproducibility of scanning in the periorbital region with 3D technology to enable objective evaluations of surgical treatment in the periorbital region was assessed. Facial 3D-scans of 15 volunteers were captured at different time points with a handheld Artec Space Spider structured light scanner. Two scans were made with a one minute interval and repeated after 1 year; for both a natural head position and with the head in a fixation-device. On assessing the area between the eyelashes and eyebrows, the medians of the average deviations between the various cross-sections of the one minute interval 3D-scans ranged from 0.17 to 0.21 mm at baseline, and from 0.10 to 0.11 mm when the minute-interval scanning was repeated one year later. The systematic differences when scanning in a natural head position and fixated position were comparable. The reproducibility of the 3D processing was excellent (intraclass correlation coefficient > 0.9). The repeated scanning deviations (baseline versus one year data) were well within the accepted clinical threshold of 1 mm. Scanning with a hand-held 3D-scanning device (Artec Space Spider) is a promising tool to assess changes in the periorbital region following surgical treatment since the median deviations are well below the clinically accepted 1 mm measuring error, for both the natural head and fixated positions
Acute Pain Assessment in Prematurely Born Infants Below 29 Weeks A Long Way to Go
Objectives: Neonates born extremely prematurely are at high risk of
acute and prolonged pain. Effective treatment requires reliable pain
assessment, which is currently missing. Our study explored whether
existing pain assessment tools and physiological indicators measure
pain and comfort accurately in this population.
Materials and Methods: We prospectively collected data in 16
neonates born at less than 29 weeks’ gestational age during 3 conditions: skin-to-skin care, rest, and heelstick procedure for capillary
blood sampling in the incubator. The neonates were video recorded
in these situations, and recordings were coded using 5 observational
pain assessment tools and numeric rating scales for pain and distress. We simultaneously collected heart rate, respiratory rate,
arterial oxygen saturation, regional cerebral oxygenation, and the
number of skin conductance peaks. All measures across the 3 conditions were compared using general linear modeling.
Results: The median gestational age was 27.1 weeks (range: 24.1 to
28.7). Forty measurement periods across the 3 conditions were
analyzed. Heart rate was significantly higher during heelstick procedures compared with during rest, with a mean difference of 10.7
beats/min (95% confidence interval [CI]: 2.7-18.6). Oxygen saturation was significantly higher during skin-to-skin care compared
with during heelstick procedures with a mean difference of 5.5%
(95% CI: 0.2-10.8). The Premature Infant Pain Profile-revised
(PIPP-R) score was significantly higher during heelstick procedures
compared with skin-to-skin care with a mean difference of 3.2
points (95% CI: 1.6-5.0).
Discussion: Pain measurement in clinical practice in prematurely
born infants below 29 weeks remains challenging. The included
behavioral and physiological indicators did not adequately distinguish between a painful situation, rest, and skin-to-skin care in
premature neonates
The educational needs of people with systemic sclerosis: a cross-sectional study using the Dutch version of the Educational Needs Assessment Tool (D-ENAT)
© 2015, The Author(s). The Dutch Educational Needs Assessment Tool (D-ENAT) systematically assesses educational needs of patients with rheumatic diseases. The present study aims to describe the educational needs of Dutch patients with systemic sclerosis (SSc). The D-ENAT was sent to 155 SSc patients registered at the outpatient clinic of a university hospital. The D-ENAT consists of 39 items in seven domains. “Each domain has different number of items therefore we normalized each domain score: (domain score/maximum)×100) and expressed in percentage to enable comparisons between domains.” A total D-ENAT score (0–156) is calculated by summing all 39 items. In addition, age, disease duration, gender, educational level, present information need (yes/no) and information need (1–4; wanting to know nothing–everything) were recorded. Univariate regression analysis was used to examine factors associated with the D-ENAT scores. The response rate was 103 out of 155 (66%). The mean % of educational needs scores (0–100%; lowest–highest) were 49% for “D-ENAT total score,” 46% for “Managing pain,” 41% for “Movement,” 43% for “Feelings,” 59% for “Disease process,” 44% for “Treatments from health professionals,” 61% for “Self-help measures” and 51% for “Support systems.” No associations between the D-ENAT total score and age, disease duration, gender and educational level were found. The D-ENAT demonstrated its ability to identify educational needs of Dutch SSc patients. SSc patients demonstrated substantial educational needs, especially in the domains: “Disease process” and “Self-help measures.” The validity and practical applicability of the D-ENAT to make an inventory of SSc patients’ educational needs require further investigation
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