| 1. |
- Fallows, Richard A., et al.
(författare)
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A LOFAR observation of ionospheric scintillation from two simultaneous travelling ionospheric disturbances
- 2020
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Ingår i: Journal of Space Weather and Space Climate. - : EDP Sciences. - 2115-7251. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the results from one of the first observations of ionospheric scintillation taken using the Low-Frequency Array (LOFAR). The observation was of the strong natural radio source Cassiopeia A, taken overnight on 18-19 August 2013, and exhibited moderately strong scattering effects in dynamic spectra of intensity received across an observing bandwidth of 10-80 MHz. Delay-Doppler spectra (the 2-D FFT of the dynamic spectrum) from the first hour of observation showed two discrete parabolic arcs, one with a steep curvature and the other shallow, which can be used to provide estimates of the distance to, and velocity of, the scattering plasma. A cross-correlation analysis of data received by the dense array of stations in the LOFAR "core" reveals two different velocities in the scintillation pattern: a primary velocity of similar to 20-40 ms(-1) with a north-west to south-east direction, associated with the steep parabolic arc and a scattering altitude in the F-region or higher, and a secondary velocity of similar to 110 ms(-1) with a north-east to south-west direction, associated with the shallow arc and a scattering altitude in the D-region. Geomagnetic activity was low in the mid-latitudes at the time, but a weak sub-storm at high latitudes reached its peak at the start of the observation. An analysis of Global Navigation Satellite Systems (GNSS) and ionosonde data from the time reveals a larger-scale travelling ionospheric disturbance (TID), possibly the result of the high-latitude activity, travelling in the north-west to south-east direction, and, simultaneously, a smaller-scale TID travelling in a north-east to south-west direction, which could be associated with atmospheric gravity wave activity. The LOFAR observation shows scattering from both TIDs, at different altitudes and propagating in different directions. To the best of our knowledge this is the first time that such a phenomenon has been reported.
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| 2. |
- Samuk, Inbal, et al.
(författare)
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Perineal Groove : An Anorectal Malformation Network, Consortium Study
- 2020
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Ingår i: Journal of Pediatrics. - : Elsevier BV. - 0022-3476. ; 222, s. 207-212
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To review the Anorectal Malformation Network experience with perineal groove (PG) focusing on its clinical characteristics and management. Study design: Data on patients with PG managed at 10 participating Anorectal Malformation Network centers in 1999-2019 were collected retrospectively by questionnaire. Results: The cohort included 66 patients (65 females) of median age 1.4 months at diagnosis. The leading referral diagnosis was anal fissure (n = 20 [30.3%]): 23 patients (34.8%) had anorectal malformations. Expectant management was practiced in 47 patients (71.2%). Eight (17%) were eventually operated for local complications. The median time to surgery was 14 months (range, 3.0-48.6 months), and the median age at surgery was 18.3 months (range, 4.8-58.0 months). In the 35 patients available for follow-up of the remaining 39 managed expectantly, 23 (65.7%) showed complete or near-complete self-epithelization by a mean age 15.3 months (range, 1-72 months) and 4 (11.4%) showed partial self-epithelization by a mean age 21 months (range, 3-48 months). Eight patients showed no resolution (5 were followed for ≤3 months). Nineteen patients (28.7%) were primarily treated with surgery. In total, 27 patients were operated. Dehiscence occurred in 3 of 27 operated patients (11.1%). Conclusions: PG seems to be an underestimated anomaly, frequently associated with anorectal malformations. Most cases heal spontaneously; therefore, expectant management is recommended. When associated with anorectal malformations requiring reconstruction, PG should be excised in conjunction with the anorectoplasty.
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| 3. |
- van der Steeg, Hendrik J.J., et al.
(författare)
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Bowel function and associated risk factors at preschool and early childhood age in children with anorectal malformation type rectovestibular fistula : An ARM-Net consortium study
- 2022
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Ingår i: Journal of Pediatric Surgery. - : Elsevier BV. - 0022-3468. ; 57:9, s. 89-96
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Tidskriftsartikel (refereegranskat)abstract
- Background: Outcome of patients operated for anorectal malformation (ARM) type rectovestibular fistula (RVF) is generally considered to be good. However, large multi-center studies are scarce, mostly describing pooled outcome of different ARM-types, in adult patients. Therefore, counseling parents concerning the bowel function at early age is challenging. Aim of this study was to evaluate bowel function of RVF-patients at preschool/early childhood age and determine risk factors for poor functional outcome. Methods: A multi-center cohort study was performed. Patient characteristics, associated anomalies, sacral ratio, surgical procedures, post-reconstructive complications, one-year constipation, and Bowel Function Score (BFS) at 4–7 years of follow-up were registered. Groups with below normal (BFS < 17; subgroups ‘poor’ ≤ 11, and ‘fair’ 11 < BFS < 17) and good outcome (BFS ≥ 17) were formed. Univariable analyses were performed to detect risk factors for outcome. Results: The study included 111 RVF-patients. Median BFS was 16 (range 6–20). The ‘below normal’ group consisted of 61 patients (55.0%). Overall, we reported soiling, fecal accidents, and constipation in 64.9%, 35.1% and 70.3%, respectively. Bowel management was performed in 23.4% of patients. Risk factors for poor outcome were tethered cord and low sacral ratio, while sacral anomalies, low sacral ratio, prior enterostomy, post-reconstructive complications, and one-year constipation were for being on bowel management. Conclusions: Although median BFS at 4–7 year follow-up is nearly normal, the majority of patients suffers from some degree of soiling and constipation, and almost 25% needs bowel management. Several factors were associated with poor bowel function outcome and bowel management. Level of Evidence: Level III.
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