scholarly journals The infancy of core-collapse supernova remnants

2021 ◽  
Vol 502 (3) ◽  
pp. 3264-3293
Author(s):  
Michael Gabler ◽  
Annop Wongwathanarat ◽  
Hans-Thomas Janka

ABSTRACT We present 3D hydrodynamic simulations of neutrino-driven supernovae (SNe) with the Prometheus-HotB code, evolving the asymmetrically expanding ejecta from shock breakout until they reach the homologous expansion phase after roughly one year. Our calculations continue the simulations for two red supergiant and two blue supergiant progenitors by Wongwathanarat et al., who investigated the growth of explosion asymmetries produced by hydrodynamic instabilities during the first second of the explosion and their later fragmentation by Rayleigh–Taylor instabilities. We focus on the late time acceleration and inflation of the ejecta caused by the heating due to the radioactive decay of 56Ni to 56Fe and by a new outward-moving shock, which forms when the reverse shock from the He/H-shell interface compresses the central part of the ejecta. The mean velocities of the iron-rich ejecta increase between 100 and 350 km s−1 (∼8–30 per cent), and the fastest 1 per cent of the iron accelerates by up to ∼1000 km s−1 (∼20–25 per cent). This ‘Ni-bubble effect’, known from 1D models, accelerates the bulk of the nickel in our 3D models and causes an inflation of the initially overdense Ni-rich clumps, which leads to underdense, extended fingers, enveloped by overdense skins of compressed surrounding matter. We also provide volume and surface filling factors as well as a spherical harmonics analysis to characterize the spectrum of Ni-clump sizes quantitatively. Three of our four models give volume filling factors larger than 0.3, consistent with what is suggested for SN 1987A by observations.

1987 ◽  
Vol 125 ◽  
pp. 126-126
Author(s):  
John R. Dickel ◽  
Eric M. Jones ◽  
Jean A. Eilek

The remnants of the Kepler's and Tycho's supernovae show a thick shell structure with a sharp outer edge and significant brightness irregularities. Models of their expansion have been constructed using a one-dimensional spherical hydrodynamics code, which includes both a leading shock and a reverse shock moving back into the ejectum. The dynamics are controlled by conditions between these shocks. Synchrotron radio emission is produced by acceleration and amplification of initial relativistic particles and fields by eddy motion at the interface between the ejected and swept-up material and at the boundaries of clumps in the surroundings with a mean separation of 5×1017 cm, Gaussian sizes of 1×1017 cm and peak densities of 3.6×10−24 cm−3. The latter was typically 10 times the mean density between clumps. A net radial orientation of the magnetic fields is attributed to stretching by Rayleigh-Taylor instabilities at the contact surfaces. To simulate true three-dimensional structure with the one-dimensional model, random contributions from four runs with varying spacings for the clumps were summed along the line of sight. The results are shown in the figure. Without clumps the observed shell is much too narrow and steep on the inside. Whether the clumpiness is a result of presupernova mass loss or a general property of the interstellar medium is not known.


2014 ◽  
Vol 9 (4) ◽  
pp. 30-35
Author(s):  
S Datta ◽  
S Maiti ◽  
G Das ◽  
A Chatterjee ◽  
P Ghosh

Background The diagnosis of classical Kawasaki Disease was based on clinical criteria. The conventional criteria is particularly useful in preventing over diagnosis, but at the same time it may result in failure to recognize the incomplete form of Kawasaki Disease. Objective To suspect incomplete Kawasaki Disease, because early diagnosis and proper treatment may reduce substantial risk of developing coronary artery abnormality which is one of the leading causes of acquired heart disease in children. Method Nine cases of incomplete Kawasaki Disease were diagnosed over a period of one year. The diagnosis of incomplete Kawasaki Disease was based on fever for five days with less than four classical clinical features and cardiac abnormality detected by 2D- echocardiography. A repeat echocardiography was done after 6 weeks of onset of illness. The patients were treated with Intravenous Immunoglobulin and/or aspirin. Result The mean age of the patients was 3.83 years and the mean duration of symptoms before diagnosis was 12.1 days. Apart from other criteria all of our patients had edema and extreme irritability. All the patients had abnormal echocardiographic finding. Five patients received only aspirin due to nonaffordability of Intravenous Immunoglobulin and four patients received both aspirin and Intravenous Immunoglobulin, but the outcome was excellent in all the cases. Conclusion Incomplete Kawasaki Disease can be diagnosed with more awareness and aspirin alone may be used as a second line therapy in case of non affordability of Intravenous Immunoglobulin. Journal of College of Medical Sciences-Nepal, 2013, Vol-9, No-4, 30-35 DOI: http://dx.doi.org/10.3126/jcmsn.v9i4.10234


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1021
Author(s):  
Bernhard Dorweiler ◽  
Pia Elisabeth Baqué ◽  
Rayan Chaban ◽  
Ahmed Ghazy ◽  
Oroa Salem

As comparative data on the precision of 3D-printed anatomical models are sparse, the aim of this study was to evaluate the accuracy of 3D-printed models of vascular anatomy generated by two commonly used printing technologies. Thirty-five 3D models of large (aortic, wall thickness of 2 mm, n = 30) and small (coronary, wall thickness of 1.25 mm, n = 5) vessels printed with fused deposition modeling (FDM) (rigid, n = 20) and PolyJet (flexible, n = 15) technology were subjected to high-resolution CT scans. From the resulting DICOM (Digital Imaging and Communications in Medicine) dataset, an STL file was generated and wall thickness as well as surface congruency were compared with the original STL file using dedicated 3D engineering software. The mean wall thickness for the large-scale aortic models was 2.11 µm (+5%), and 1.26 µm (+0.8%) for the coronary models, resulting in an overall mean wall thickness of +5% for all 35 3D models when compared to the original STL file. The mean surface deviation was found to be +120 µm for all models, with +100 µm for the aortic and +180 µm for the coronary 3D models, respectively. Both printing technologies were found to conform with the currently set standards of accuracy (<1 mm), demonstrating that accurate 3D models of large and small vessel anatomy can be generated by both FDM and PolyJet printing technology using rigid and flexible polymers.


Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 457
Author(s):  
Isabel María Introzzi ◽  
María Marta Richard’s ◽  
Yesica Aydmune ◽  
Eliana Vanesa Zamora ◽  
Florencia Stelzer ◽  
...  

Recent studies suggest that the developmental curves in adolescence, related to the development of executive functions, could be fitted to a non-linear trajectory of development with progressions and retrogressions. Therefore, the present study proposes to analyze the pattern of development in Perceptual Inhibition (PI), considering all stages of adolescence (early, middle, and late) in intervals of one year. To this aim, we worked with a sample of 275 participants between 10 and 25 years, who performed a joint visual and search task (to measure PI). We have fitted ex-Gaussian functions to the probability distributions of the mean response time across the sample and performed a covariance analysis (ANCOVA). The results showed that the 10- to 13-year-old groups performed similarly in the task and differ from the 14- to 19-year-old participants. We found significant differences between the older group and all the rest of the groups. We discuss the important changes that can be observed in relation to the nonlinear trajectory of development that would show the PI during adolescence.


2019 ◽  
pp. 112070001987482
Author(s):  
Arthur J Kievit ◽  
Johannes G G Dobbe ◽  
Wouter H Mallee ◽  
Leendert Blankevoort ◽  
Geert J Streekstra ◽  
...  

Introduction: We tested whether a mechanical device (such as Hipsecure) to pinpoint the anterior pelvic plane (APP) as a guide can improve acetabular cup placement. To assess accuracy we asked: (1) is the APP an effective guide to position acetabular cup placement within acceptable ° of divergence from the optimal 40° inclination and 15° anteversion; (2) could a mechanical device increase the number of acetabular cup placements within Lewinnek’s safe zone (i.e. inclination 30° to 50°; anteversion 5° to 25°)? Methods: 16 cadaveric specimens were used to assess the 3D surgical success of using a mechanical device APP to guide acetabular cup placement along the APP. We used the Hipsecure mechanical device to implant acetabular cups at 40° inclination and 15° anteversion. Subequently, all cadaveric specimens with implants were scanned with a CT and 3D models were created of the pelvis and acetabular cups to assess the outcome in terms of Lewinnek’s safe zones. Results: The mean inclination of the 16 implants was 40.6° (95% CI, 37.7–43.4) and the mean anteversion angle was 13.4° (95% CI, 10.7–16.1). All 16 cup placements were within Lewinnek’s safe zone for inclination (between 30° and 50°) and all but 2 were within Lewinnek’s safe zone for anteversion (between 5° and 25°). Conclusion: In cadaveric specimens, the use of a mechanical device and the APP as a guide for acetabular cup placement resulted in good positioning with respect to both of Lewinnek’s safe zones.


Author(s):  
Vagner de Alencar Arnaut de Toledo ◽  
Regina Helena Nogueira-Couto

This experiment was carried out to study the internal temperature regulation of a colony of Africanized honey bees (AFR), compared with hybrid Caucasian (CAU), Italian (ITA), and Carniolan (CAR) bees, during the period of one year and different size hives located in a sub-tropical region. The instant internal temperature, 33.7 ± 1.5° C for the AFR, 33.5 ± 1.4° C for the CAU, 33.7 ± 1.5° C for the ITA and 33.8 ± 1.4° C for the CAR, did not show any significant difference (P>0.05). The maximum temperature (36.1 ± 2.3° C) was statistically different (P<0.05) from the minimum (27.6 ± 5.3° C). There was no difference (P>0.05) in the mean internal temperature, between the nucleus (31.7 ± 6.3° C) and the brood nest (32.1 ± 5.3° C) measured between two and four o'clock in the afternoon.


2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1080-1080
Author(s):  
N. Ziade ◽  
S. Al Emadi ◽  
M. Abu Jbara ◽  
S. Saad ◽  
L. Kibbi ◽  
...  

Background:Involving the patients with rheumatoid arthritis (RA) in the assessment of their disease may increase their adherence to treatment, improve the disease outcomes and facilitate the application of telehealth. We previously reported an excellent concordance between the Disease Activity Score (DAS-28) performed by physicians and patients at the baseline visit of this prospective study (1).Objectives:To evaluate the persistence of the concordance between the physician’ and the patient’s assessment of disease activity in RA using DAS-28 after one year.Methods:At the baseline visit, patients with RA from 7 Middle Eastern Arab Countries (MEAC) were briefed about DAS-28 by their rheumatologist during a routine consultation and given smartphone access to a video in Arabic language explaining the performance of DAS-28. At 3, 6 and 12 months (± 3 months), the patients were asked to self-report DAS-28, blinded to the physician’s assessment. Concordance between the continuous DAS-28 at each visit was calculated using paired t-test numerically and the Bland-Altman method graphically. Agreement between physician- and patient-DAS categories (remission, low-, moderate- and high disease activity) was calculated at each visit using weighted kappa for category comparison. Weighted kappa of the different agreements were compared over time using their respective confidence intervals (CIs). Predictive factors of positive concordance between physician and patient-DAS were identified using binary logistic regression.Results:The study included 428 patients over a period of three years (2018 to 2020). The mean age of participants was 49.8 years, 82.5% were females, 44.3% had a university degree and the mean disease duration was 11.4 years.At baseline, the average patient-DAS was higher (4.06 (±1.52)) than the physician-DAS (3.97 (±1.52)). The mean difference was -0.09 [95%CI -0.14; -0.04] and most of the pairs were within the limit of agreement in the Bland-Altman graph, indicating a good concordance, particularly in cases of remission.During the study follow-up, 299 patients consulted for visit 2 (69.9% of the total population), 232 for visit 3 (54.2%) and 199 for visit 4 (46.5%). The weighted kappa was 0.80 [95%CI 0.76;0.85] at visit 1 and 0.79 [95%CI 0.72;0.88] at visit 4 (Figure 1 showing kappa for DAS-28, CDAI and SDAI as well). A minor numerical decrease in kappa was observed over time; however, the CIs were overlapping over the four visits and the agreement was considered stable, remaining in the excellent range. At visit 4, a positive concordance between the physician- and the patient-DAS was associated with the profession (lower in blue collar, p=0.001), the educational level (higher in high school and university, p=0.034) and the baseline physician’s DAS (higher in high disease activity, p=0.46).Conclusion:The agreement between the DAS-28 performed by the physician and by the patient was excellent at baseline and remained stable over one year. A positive concordance was associated with the profession, the educational level and the level of disease activity. The present study can help the rheumatologist make informed decisions about the patients who may be suitable for a remote evaluation of their disease activity, that can be of particular interest in the context of the COVID-19 pandemic.References:[1]Ziade N, Saad S, al Mashaleh M, et al. Perceptions of Patients with Rheumatoid Arthritis about Self-Assessment of Disease Activity after Watching an Educational Video: Qualitative Pilot Results from the Auto-DAS in Middle Eastern Arab Countries Study [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 10).Acknowledgements:The authors would like to acknowledge the patients for participating in the study and the assistants/ students/ nurses who assisted in the data collection: Dr. Fatima Abdul Majeed Al Hawaj, M. Atef Ahmed, M. Mohammad Alhusamiah, Ms Raquel De Guzman, Ms Lina Razzouk.Disclosure of Interests:None declared


2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 469-470
Author(s):  
Sara Nowakowski ◽  
Javad Razjouyan ◽  
Amir Sharafkhaneh ◽  
Mark Kunik ◽  
Aanand Naik

Abstract Few studies have longitudinally investigated the association between objectively measured sleep and time to develop dementia. This study leverages polysomnography (PSG) sleep data extracted from the VA national electronic health records (VA-EHR) to assess the association between sleep and time to develop dementia. We identified 61,165 PSG reports from the VA-EHR from 2000 to 2019 using CPT codes. Patients who developed dementia were identified using all-cause dementia ICD-9/10 codes documented on two separate visits starting one year after the PSG study until the end of 2019 in a 1-year sliding period (n=1,534). Using the first appearance of ICD-9/10 code as dementia onset time, patients were clustered into 3 groups of early-, mid-, and late time to develop dementia (mean = 2.7, 7.5, 12.8 years, respectively). Natural language processing was used to extract sleep efficiency (SE) and sleep onset latency (SOL). Univariate analysis was used to compare the groups. After adjusting for age, SE was significantly higher in the late (76%) vs early (69%) group and SOL was significantly shorter in late (21m) versus early (33m) group. SE was higher and SOL was shorter in patients who developed dementia later compared to those who developed dementia earlier. Greater sleep continuity in late dementia onset group suggests that sleep may be a modifiable risk factor that could potentially delay the onset of dementia.


2021 ◽  
Vol 13 (4) ◽  
pp. 829
Author(s):  
Teresa Gracchi ◽  
Guglielmo Rossi ◽  
Carlo Tacconi Stefanelli ◽  
Luca Tanteri ◽  
Rolando Pozzani ◽  
...  

Unmanned aerial vehicle (UAV) photogrammetry has recently become a widespread technique to investigate and monitor the evolution of different types of natural processes. Fluvial geomorphology is one of such fields of application where UAV potentially assumes a key role, since it allows for overcoming the intrinsic limits of satellite and airborne-based optical imagery on one side, and in situ traditional investigations on the other. The main purpose of this paper was to obtain extensive products (digital terrain models (DTMs), orthophotos, and 3D models) in a short time, with low costs and at a high resolution, in order to verify the capability of this technique to analyze the active geomorphic processes on a 12 km long stretch of the French–Italian Roia River at both large and small scales. Two surveys, one year apart from each other, were carried out over the study area and a change detection analysis was performed on the basis of the comparison of the obtained DTMs to point out and characterize both the possible morphologic variations related to fluvial dynamics and modifications in vegetation coverage. The results highlight how the understanding of different fluvial processes may be improved by appropriately exploiting UAV-based products, which can thus represent a low-cost and non-invasive tool to crucially support decisionmakers involved in land management practices.


Author(s):  
Abigail Niesen ◽  
Anna L Garverick ◽  
Maury Hull

Abstract Maximum total point motion (MTPM), the point on a baseplate that migrates the most, has been used to assess the risk of tibial baseplate loosening using radiostereometric analysis (RSA). Two methods for determining MTPM for model-based RSA are to use either 5 points distributed around the perimeter of the baseplate or to use all points on the 3D model. The objectives were to quantify the mean difference in MTPM using 5 points vs. all points, compute the percent error relative to the 6-month stability limit for groups of patients, and to determine the dependency of differences in MTPM on baseplate size and shape. A dataset of 10,000 migration values was generated using the mean and standard deviation of migration in six degrees of freedom at 6 months from an RSA study. The dataset was used to simulate migration of 3D models (two baseplate shapes and two baseplate sizes) and calculate the difference in MTPM using 5 virtual points vs. all points and the percent error (i.e. difference in MTPM/stability limit) relative to the 6-month stability limit. The difference in MTPM was about 0.02 mm, or 4% percent relative to the 6-month stability limit, which is not clinically important. Furthermore, results were not affected by baseplate shape or size. Researchers can decide whether to use 5 points or all points when computing MTPM for model-based RSA. The authors recommend using 5 points to maintain consistency with marker-based RSA.


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