23 research outputs found

    Hydrodynamic Models of Line-Driven Accretion Disk Winds III: Local Ionization Equilibrium

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    We present time-dependent numerical hydrodynamic models of line-driven accretion disk winds in cataclysmic variable systems and calculate wind mass-loss rates and terminal velocities. The models are 2.5-dimensional, include an energy balance condition with radiative heating and cooling processes, and includes local ionization equilibrium introducing time dependence and spatial dependence on the line radiation force parameters. The radiation field is assumed to originate in an optically thick accretion disk. Wind ion populations are calculated under the asumption that local ionization equilibrium is determined by photoionization and radiative recombination, similar to a photoionized nebula. We find a steady wind flowing from the accretion disk. Radiative heating tends to maintain the temperature in the higher density wind regions near the disk surface, rather than cooling adiabatically. For a disk luminosity Ldisk = Lsun, white dwarf mass Mwd = 0.6 Msun, and white dwarf radii Rwd = 0.01 Rsun, we obtain a wind mass-loss rate of dMwind/dt =4E-12 Msun/yr, and a terminal velocity of ~ 3000 km/s. These results confirm the general velocity and density tructures found in our earlier constant ionization equilibrium adiabatic CV wind models. Further we establish here 2.5D numerical models that can be extended to QSO/AGN winds where the local ionization equilibrium will play a crucial role in the overall dynamics.Comment: 43 pages, 12 figures, to be published in The Astrophysical Journa

    Clinical, radiologic, pathologic, and molecular characteristics of long-term survivors of diffuse intrinsic pontine glioma (DIPG): a collaborative report from the International and European Society for Pediatric Oncology DIPG registries

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    Purpose Diffuse intrinsic pontine glioma (DIPG) is a brainstem malignancy with a median survival of < 1 year. The International and European Society for Pediatric Oncology DIPG Registries collaborated to compare clinical, radiologic, and histomolecular characteristics between short-term survivors (STSs) and long-term survivors (LTSs). Materials and Methods Data abstracted from registry databases included patients from North America, Australia, Germany, Austria, Switzerland, the Netherlands, Italy, France, the United Kingdom, and Croatia. Results Among 1,130 pediatric and young adults with radiographically confirmed DIPG, 122 (11%) were excluded. Of the 1,008 remaining patients, 101 (10%) were LTSs (survival ≥ 2 years). Median survival time was 11 months (interquartile range, 7.5 to 16 months), and 1-, 2-, 3-, 4-, and 5-year survival rates were 42.3% (95% CI, 38.1% to 44.1%), 9.6% (95% CI, 7.8% to 11.3%), 4.3% (95% CI, 3.2% to 5.8%), 3.2% (95% CI, 2.4% to 4.6%), and 2.2% (95% CI, 1.4% to 3.4%), respectively. LTSs, compared with STSs, more commonly presented at age < 3 or > 10 years (11% v 3% and 33% v 23%, respectively; P < .001) and with longer symptom duration ( P < .001). STSs, compared with LTSs, more commonly presented with cranial nerve palsy (83% v 73%, respectively; P = .008), ring enhancement (38% v 23%, respectively; P = .007), necrosis (42% v 26%, respectively; P = .009), and extrapontine extension (92% v 86%, respectively; P = .04). LTSs more commonly received systemic therapy at diagnosis (88% v 75% for STSs; P = .005). Biopsies and autopsies were performed in 299 patients (30%) and 77 patients (10%), respectively; 181 tumors (48%) were molecularly characterized. LTSs were more likely to harbor a HIST1H3B mutation (odds ratio, 1.28; 95% CI, 1.1 to 1.5; P = .002). Conclusion We report clinical, radiologic, and molecular factors that correlate with survival in children and young adults with DIPG, which are important for risk stratification in future clinical trials

    Clinical Outcomes and Patient-Matched Molecular Composition of Relapsed Medulloblastoma

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    PURPOSE We sought to investigate clinical outcomes of relapsed medulloblastoma and to compare molecular features between patient-matched diagnostic and relapsed tumors. METHODS Children and infants enrolled on either SJMB03 (NCT00085202) or SJYC07 (NCT00602667) trials who experienced medulloblastoma relapse were analyzed for clinical outcomes, including anatomic and temporal patterns of relapse and postrelapse survival. A largely independent, paired molecular cohort was analyzed by DNA methylation array and next-generation sequencing. RESULTS A total of 72 of 329 (22%) SJMB03 and 52 of 79 (66%) SJYC07 patients experienced relapse with significant representation of Group 3 and wingless tumors. Although most patients exhibited some distal disease (79%), 38% of patients with sonic hedgehog tumors experienced isolated local relapse. Time to relapse and postrelapse survival varied by molecular subgroup with longer latencies for patients with Group 4 tumors. Postrelapse radiation therapy among previously nonirradiated SJYC07 patients was associated with long-term survival. Reirradiation was only temporizing for SJMB03 patients. Among 127 patients with patient-matched tumor pairs, 9 (7%) experienced subsequent nonmedulloblastoma CNS malignancies. Subgroup (96%) and subtype (80%) stabilities were largely maintained among the remainder. Rare subgroup divergence was observed from Group 4 to Group 3 tumors, which is coincident with genetic alterations involving MYC, MYCN, and FBXW7. Subgroup-specific patterns of alteration were identified for driver genes and chromosome arms. CONCLUSION Clinical behavior of relapsed medulloblastoma must be contextualized in terms of up-front therapies and molecular classifications. Group 4 tumors exhibit slower biological progression. Utility of radiation at relapse is dependent on patient age and prior treatments. Degree and patterns of molecular conservation at relapse vary by subgroup. Relapse tissue enables verification of molecular targets and identification of occult secondary malignancies

    Clinical outcomes and patient-matched molecular composition of relapsed medulloblastoma

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    © 2021 by American Society of Clinical Oncology. Creative Commons Attribution Non-Commercial No Derivatives 4.0 License: https://creativecommons.org/licenses/by-nc-nd/4.0/Purpose: We sought to investigate clinical outcomes of relapsed medulloblastoma and to compare molecular features between patient-matched diagnostic and relapsed tumors. Methods: Children and infants enrolled on either SJMB03 (NCT00085202) or SJYC07 (NCT00602667) trials who experienced medulloblastoma relapse were analyzed for clinical outcomes, including anatomic and temporal patterns of relapse and postrelapse survival. A largely independent, paired molecular cohort was analyzed by DNA methylation array and next-generation sequencing. Results: A total of 72 of 329 (22%) SJMB03 and 52 of 79 (66%) SJYC07 patients experienced relapse with significant representation of Group 3 and wingless tumors. Although most patients exhibited some distal disease (79%), 38% of patients with sonic hedgehog tumors experienced isolated local relapse. Time to relapse and postrelapse survival varied by molecular subgroup with longer latencies for patients with Group 4 tumors. Postrelapse radiation therapy among previously nonirradiated SJYC07 patients was associated with long-term survival. Reirradiation was only temporizing for SJMB03 patients. Among 127 patients with patient-matched tumor pairs, 9 (7%) experienced subsequent nonmedulloblastoma CNS malignancies. Subgroup (96%) and subtype (80%) stabilities were largely maintained among the remainder. Rare subgroup divergence was observed from Group 4 to Group 3 tumors, which is coincident with genetic alterations involving MYC, MYCN, and FBXW7. Subgroup-specific patterns of alteration were identified for driver genes and chromosome arms. Conclusion: Clinical behavior of relapsed medulloblastoma must be contextualized in terms of up-front therapies and molecular classifications. Group 4 tumors exhibit slower biological progression. Utility of radiation at relapse is dependent on patient age and prior treatments. Degree and patterns of molecular conservation at relapse vary by subgroup. Relapse tissue enables verification of molecular targets and identification of occult secondary malignancies.info:eu-repo/semantics/publishedVersio

    The Murchison Widefield Array: The Square Kilometre Array Precursor at Low Radio Frequencies

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    The Murchison Widefield Array (MWA) is one of three Square Kilometre Array Precursor telescopes and is located at the Murchison Radio-astronomy Observatory in the Murchison Shire of the mid-west of Western Australia, a location chosen for its extremely low levels of radio frequency interference. The MWA operates at low radio frequencies, 80–300 MHz, with a processed bandwidth of 30.72 MHz for both linear polarisations, and consists of 128 aperture arrays (known as tiles) distributed over a ~3-km diameter area. Novel hybrid hardware/software correlation and a real-time imaging and calibration systems comprise the MWA signal processing backend. In this paper, the as-built MWA is described both at a system and sub-system level, the expected performance of the array is presented, and the science goals of the instrument are summarised

    Preference structure in request sequences: What about role-play?

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    This Discussion Note argues that role-plays of request sequences tend to violate a norm of preference structure observed in naturally occurring interactions. It thereby contributes to our understanding of the validity of role-play as a tool for examining pragmatic performance. The method of role-play is extremely popular in the field of L2 pragmatics (e.g., Al-Ghatani and Roever, 2012, 2018; Bella, 2014; Huth, 2006; Taleghani-Nikazm and Huth, 2010). Also, as observed by Felix-Brasdefer (2018) and Schneider (2018), it is also commonly used for research in cross-cultural pragmatics (e.g. Ebsworth and Kodama, 2011; Felix-Brasdefer, 2003, 2008; Reiter and Marquez, 2000), as well as in variational pragmatics (e.g. Felix-Brasdefer, 2009; Fuentes-Rodriguez, Placencia and Palma-Fahey, 2016; Placencia et al., 2015). Moreover, such studies often entail role-plays of request sequences specifically. First, as background, the Note introduces the notion of preference structure, outlines preference norms for request se- quences, and reviews evidence on how closely role-played interactions resemble naturally occurring interactions. The Note then presents an extended data extract to illustrate the present finding that role-plays tend to violate the relevant norm of preference structure. Last, it offers explanations for that finding, and discusses implications for role-play as a data elicitation method in pragmatics researc

    Pembelajaran Bahasa Asing pada Perguruan Tinggi Keagamaan Islam Negeri: Kebijakan dan Hasil

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    This chapter by Imelda Wahyuni examines the teaching of Arabic and English at a State Islamic Institute (IAIN) in Kendari, Southeat Sulawesi. What lends the study special interest is that it examines that teaching through the lense of a Communicative Approach

    Supporting families through paediatric brain tumour: Unmet needs and suggestions for change

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    ObjectiveFrom diagnosis and beyond, a paediatric brain tumour and its treatment impact the child and their family in a myriad of ways. While it is considered best practice to offer ongoing psychosocial support for all family members, there is little scholarly investigation of both families' experiences and the practical implications of offering such care. We aimed to explore families' experiences of paediatric brain tumour and their associated psychosocial health service needs.MethodsFamilies receiving care at the Queensland Children's Hospital in Brisbane, Australia, for a child (0–18 years) who had been diagnosed with a brain tumour between 2019 and 2022 were invited to be interviewed about their experiences. Using qualitative description, we analysed these interviews to identify families' unmet psychosocial health service needs and their suggestions for improvement.ResultsTwenty-three clinically and socially diverse families were represented. While parents/carers expressed gratitude for the care their child had received, most also described unmet needs for the broader family. We identified three primary needs to be addressed: (1) parents want accessible psychological/emotional support for themselves; (2) parents/carers want additional guidance to navigate the hospital setting to reduce uncertainty and loss of control; and (3) parents want support to minimise treatment-associated trauma for their child.ConclusionsOur findings evidence the need for improved family-centred psychosocial care within paediatric brain tumour care in Queensland, Australia. We propose a counselling and care coordination intervention to support parents/carers to care for themselves, their child, and their family through an extremely challenging experience

    Incidence and survival for childhood central nervous system tumours in Australia, 1983–2016

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    Purpose: To investigate incidence and survival of childhood tumours of the central nervous system (CNS) by histological subtype, tumour behaviour and tumour grade. Methods: National, population-based data on all children under 15 years old diagnosed with a CNS tumour between 1983 and 2016 were sourced from the Australian Childhood Cancer Registry. Incidence rate trends were calculated using Joinpoint regression. Relative survival was calculated using the cohort method, with changes in survival over time by cancer type and tumour grade assessed by multivariable flexible parametric survival modelling. Results: The study cohort included 4914 patients, with astrocytoma (n = 2181, 44%) and embryonal tumours (n = 931, 19%) the most common diagnostic subgroups. Almost half (n = 2181, 44%) of all tumours were classified as high grade (III or IV). Incidence rates increased by 29% between 1983 and 2016, with high grade tumours rising by an annual average of + 1.1% (95% CI = + 0.7%, + 1.5%, p < 0.001). 5-year survival for all patients combined was 72% (95% CI = 71–74%), ranging from 50% (46–54%) for those with other gliomas to 81% (79–83%) for astrocytoma (p < 0.001). Survival improved over time for grade II and III ependymomas but not for patients with astrocytoma irrespective of grade. Conclusion: Improvements in diagnostic technology leading to more precise tumour classification are likely to explain some of the differences in incidence rate trends by histological type and grade. While improvements in survival over time were noted for some tumours, outcomes remained poor among patients with high-grade astrocytoma
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