Hasil untuk "astro-ph.HE"

Menampilkan 20 dari ~1267963 hasil · dari CrossRef, DOAJ, arXiv, Semantic Scholar

JSON API
S2 Open Access 2020
Radiation Therapy for Cervical Cancer: Executive Summary of an ASTRO Clinical Practice Guideline.

J. Chino, C. Annunziata, S. Beriwal et al.

PURPOSE This guideline reviews the evidence and provides recommendations for the indications and appropriate techniques of radiation therapy (RT) in the treatment of nonmetastatic cervical cancer. METHODS The American Society for Radiation Oncology convened a task force to address 5 key questions focused on the use of RT in definitive and postoperative management of cervical cancer. These questions included the indications for postoperative and definitive RT, the use of chemotherapy in sequence or concurrent with RT, the use of intensity modulated radiation therapy (IMRT), and the indications and techniques of brachytherapy. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength. RESULTS The guideline recommends postoperative RT for those with intermediate risk factors, and chemoradiation for those with high-risk factors. In the definitive setting, chemoradiation is recommended for stages IB3-IVA, and RT or chemoradiation is conditionally recommended for stages IA1-IB2 if medically inoperable. IMRT is recommended for postoperative RT and conditionally recommended for definitive RT, for the purposes of reducing acute and late toxicity. Brachytherapy is strongly recommended for all women receiving definitive RT, and several recommendations are made for target dose and fractionation, the use of intraoperative imaging, volume-based planning, and recommendations for doses limits for organs at risk. CONCLUSIONS There is strong evidence supporting the use of RT with or without chemotherapy in both definitive and postoperative settings. Brachytherapy is an essential part of definitive management and volumetric planning is recommended. IMRT may be used for the reduction of acute and late toxicity. The use of radiation remains an essential component for women with cervical cancer to achieve cure.

221 sitasi en Medicine
arXiv Open Access 2026
GW190711_030756 and GW200114_020818: astrophysical interpretation of two asymmetric binary black hole mergers in the IAS catalog

Tousif Islam, Tejaswi Venumadhav, Digvijay Wadekar et al.

We provide a comprehensive analysis of GW190711_030756 and GW200114_020818, two of the most significant binary black hole merger candidates in the IAS catalog, with probabilities of astrophysical origin $p_{\rm astro}=0.99$ and $0.71$, respectively, and signal-to-noise ratios of approximately $10.0$ and $13.4$. We employ numerical relativity surrogate models to infer both the source properties and the remnant properties of these two candidates. We find that both GW190711_030756 and GW200114_020818 are asymmetric-mass binaries, with inferred mass ratios of $0.35^{+0.32}_{-0.15}$ and $\leq 0.20$. In addition, GW200114_020818 is inferred to have a source-frame total mass of approximately $220M_{\odot}$ and highly spinning black holes, with primary (secondary) dimensionless spin magnitudes of $0.96^{+0.03}_{-0.07}$ ($0.84^{+0.13}_{-0.34}$), closely resembling GW231123_135430. We further find that GW200114\_020818 has a confidently negative effective inspiral spin of $χ_{\rm eff}=-0.60^{+0.22}_{-0.13}$ and exhibits strong spin precession, characterized by an effective precession parameter of $χ_{\rm p}=0.60^{+0.21}_{-0.19}$. GW200114_020818 (when considered alongside GW231123_135430) points towards an emerging population of massive, rapidly spinning BBH mergers. While GW231123_135430 is consistent with mergers in globular clusters, producing systems like GW200114_020818 in such environments remains difficult even under hierarchical merger scenarios. The probability that the remnant black hole of GW190711_030756 (GW200114_020818) is retained in its host environment is $0.079$ ($0.0002$), $0.62$ ($0.965$), and $0.997$ ($1$) if the merger occurred in a globular cluster, a nuclear star cluster, or an elliptical galaxy, respectively.

en astro-ph.HE, gr-qc
arXiv Open Access 2026
Nuclear astrophysics

Roland Diehl, Michael Wiescher

Reactions between atomic nuclei are measured in great detail in terrestrial laboratory experiments; transferring and extrapolating this knowledge to how the same reactions act within cosmic environments presents major challenges. Cross-disciplinary efforts are needed in view of the many nuclear reactions that govern the chemical evolution of the universe, and occur in a broad range of stellar plasma conditions that require astrophysical exploration. Since the early identification of 'processes' of nucleosynthesis, new insights have been obtained on the complexity of nuclear reaction mechanisms. We use 12C induced capture and fusion processes to illustrate the challenge of low-energy measurements and of using theoretical methods to extrapolate measurements towards energy regimes within cosmic sources. Particle beam experiments at accelerator facilities above and deep underground simulate stellar reactions, new experimental facilities and methods complement these, and this is further complemented by improved theoretical tools to calculate the quantum effects of nuclear reactions at the various cosmic conditions. Astronomical signatures of cosmic nuclear reactions are deduced from light curves characterizing cosmic explosions through gamma-ray lines and presolar grains to the detection of rare neutrino particles from our Sun to distant cosmic events. High resolution spectroscopy of stars has been expanded to objects measured in the X-ray and the gamma energy range of the electromagnetic spectrum. Astro-seismology and isotopic analysis of meteoritic inclusions provide new tools. Chemical-evolution models describe the complex dynamics during the evolution of galaxies. This article summarizes the experimental and theoretical work, and the broad range of observational tools that test the experimental data and the theoretical interpretation of nuclear processes in the cosmos.

en astro-ph.HE
S2 Open Access 2019
Neutrino–nuclear responses for astro-neutrinos, single beta decays and double beta decays

H. Ejiri, J. Suhonen, K. Zuber

Abstract Neutrino–nuclear responses associated with astro-neutrinos, single beta decays and double beta decays are crucial in studies of neutrino properties of interest for astro-particle physics. The present report reviews briefly recent studies of the neutrino–nuclear responses from both experimental and theoretical points of view in order to obtain a consistent understanding of the many facets of the neutrino–nuclear responses. Subjects discussed in this review include (i) experimental studies of neutrino–nuclear responses by means of single beta decays, charge-exchange nuclear reactions, muon- photon- and neutrino–nuclear reactions, and nucleon-transfer reactions, (ii) implications of and discussions on neutrino–nuclear responses for single beta decays, for astro-neutrinos, and for astro-neutrino nucleosynthesis, (iii) theoretical aspects of neutrino–nuclear responses for beta and double beta decays, for nuclear muon capture and for neutrino–nucleus scattering, and (iv) critical discussions on nucleonic and non-nucleonic spin–isospin correlations and renormalization (quenching or enhancement) effects on the axial weak coupling. Remarks are given on perspectives of experimental and theoretical studies of the neutrino–nuclear responses and on future experiments of double beta decays.

207 sitasi en Physics
S2 Open Access 2020
Radiation Therapy for Small Cell Lung Cancer: An ASTRO Clinical Practice Guideline.

C. Simone, J. Bogart, A. Cabrera et al.

PURPOSE Several sentinel phase III randomized trials have recently been published challenging traditional radiation therapy (RT) practices for small cell lung cancer (SCLC). This American Society for Radiation Oncology guideline reviews the evidence for thoracic RT and prophylactic cranial irradiation (PCI) for both limited-stage (LS) and extensive-stage (ES) SCLC. METHODS The American Society for Radiation Oncology convened a task force to address 4 key questions focused on indications, dose fractionation, techniques and timing of thoracic RT for LS-SCLC, the role of stereotactic body radiation therapy (SBRT) compared with conventional RT in stage I or II node negative SCLC, PCI for LS-SCLC and ES-SCLC, and thoracic consolidation for ES-SCLC. Recommendations were based on a systematic literature review and created using a consensus-building methodology and system for grading evidence quality and recommendation strength. RESULTS The task force strongly recommends definitive thoracic RT administered once or twice daily early in the course of treatment for LS-SCLC. Adjuvant RT is conditionally recommended in surgically resected patients with positive margins or nodal metastases. Involved field RT delivered using conformal advanced treatment modalities to postchemotherapy volumes is also strongly recommended. For patients with stage I or II node negative disease, SBRT or conventional fractionation is strongly recommended, and chemotherapy should be delivered before or after SBRT. In LS-SCLC, PCI is strongly recommended for stage II or III patients who responded to chemoradiation, conditionally not recommended for stage I patients, and should be a shared decision for patients at higher risk of neurocognitive toxicities. In ES-SCLC, radiation oncologist consultation for consideration of PCI versus magnetic resonance surveillance is strongly recommended. Lastly, the use of thoracic RT is strongly recommended in select patients with ES-SCLC after chemotherapy treatment, including a conditional recommendation in those responding to chemotherapy and immunotherapy. CONCLUSIONS RT plays a vital role in both LS-SCLC and ES-SCLC. These guidelines inform best clinical practices for local therapy in SCLC.

171 sitasi en Medicine
arXiv Open Access 2025
Theory, Simulations and Observations of Stellar Mergers

Fabian R. N. Schneider

Stellar mergers are responsible for a large variety of astrophysical phenomena. They form blue straggler stars, give rise to spectacular transients, and produce some of the most massive stars in the Universe. Here, we focus on mergers from binary evolution and stellar collisions but do not cover mergers involving compact objects. We review how mergers come about, explain the physics and outcome of the merger process, discuss the evolution and ultimate fates of merged stars, and relate to observations. Our main conclusions are: (i) Mergers of main-sequence stars often fully rejuvenate and have interior structures similar to genuine single stars. (ii) Contrarily, mergers involving post-main-sequence stars can have interior structures that cannot be achieved by single-star evolution. Such merged stars may become long-lived blue supergiants that can explode in SN1987A-like events, interacting and superluminous supernovae, ultra-long gamma-ray bursts or collapse into very massive black holes. These black holes may even populate the pair-instability-supernova black-hole mass gap. (iii) Strong magnetic fields are produced in stellar mergers. Merged stars may thus be at the origin of some magnetic OBA stars and their descendants, highly magnetic white dwarfs and neutron stars. (iv) Initially, stellar merger products rotate rapidly, but there are several mechanisms that can quickly spin them down. Hence, merged stars may be rather slow rotators for most of their evolution.

en astro-ph.SR, astro-ph.GA
S2 Open Access 2019
Radiation Therapy for Pancreatic Cancer: Executive Summary of an ASTRO Clinical Practice Guideline.

M. Palta, D. Godfrey, K. Goodman et al.

PURPOSE This guideline systematically reviews the evidence for treatment of pancreatic cancer with radiation in the adjuvant, neoadjuvant, definitive, and palliative settings and provides recommendations on indications and technical considerations. METHODS AND MATERIALS The American Society for Radiation Oncology convened a task force to address 7 key questions focused on radiation therapy, including dose fractionation and treatment volumes, simulation and treatment planning, and prevention of radiation-associated toxicities. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength. RESULTS The guideline conditionally recommends conventionally fractionated or stereotactic body radiation for neoadjuvant and definitive therapy in certain patients and conventionally fractionated regimens for adjuvant therapy. The task force suggests a range of appropriate dose-fractionation schemes and provides recommendations on target volumes and sequencing of radiation and chemotherapy. Motion management, daily image guidance, use of contrast, and treatment with modulated techniques are all recommended. The task force supported prophylactic antiemetic medication, and patients may also benefit from medications to reduce acid secretion. CONCLUSIONS The role of radiation in the management of pancreatic cancer is evolving, with many ongoing areas of active investigation. Radiation therapy is likely to become even more important as new systemic therapies are developed and there is increased focus on controlling local disease. It is important that the nuances of available data are discussed with patients and families and that care be coordinated in a multidisciplinary fashion.

166 sitasi en Medicine
CrossRef Open Access 2023
Sobre Buracos Negros

Felipe Tovar Falciano

Buracos negros são objetos astrofísicos com propriedades muito particulares e fascinante. A partir de hipóteses genéricas, como a validade da teoria da relatividade geral, é possível provar teoremas que garantem a existência e propriedades desses objetos. Porém, apenas a observação e os experimentos são capazes de testar e verificar afirmações sobre fenômenos naturais. Seguindo este raciocínio, iremos desenvolver os conceitos básicos do que é um buraco negro, explicitar algumas de suas propriedades peculiares e por fim pontuar as observações que comprovaram a existência desses objetos compactos.

CrossRef Open Access 2023
termodinâmica de buracos negros

Tiago Fernandes

Buracos negros existem em todo lado no nosso universo. Segundo a relatividade geral, estes objetos são clássicos e não emitem qualquer radiação, são negros. No entanto, quando se considera campos quânticos, verifica-se que os buracos negros são na realidade objetos termodinâmicos e que não são assim tão negros. Neste artigo, fazemos a exposição de como um buraco negro é termodinâmico. Primeiro, fazemos uma exposição breve da descrição clássica dos buracos negros e as suas quatro leis de mecânica. Depois, fazemos a exposição dos primeiros trabalhos que avançaram a ideia de que os buracos negros são termodinâmicos. Finalmente, fazemos a exposição do formalismo que permite tratar a termodinâmica de espaços-tempos contendo buracos negros e referimos muito brevemente a sua investigação recente.

arXiv Open Access 2023
The Evolution of Massive Binary Stars

Pablo Marchant, Julia Bodensteiner

Massive stars play a major role in the evolution of their host galaxies, and serve as important probes of the distant Universe. It has been established that the majority of massive stars reside in close binaries and will interact with their companion stars during their lifetime. Such interactions drastically alter their life cycles and complicate our understanding of their evolution, but are also responsible for the production of interesting and exotic interaction products. - Extensive observation campaigns with well-understood detection sensitivities have allowed to convert the observed properties into intrinsic characteristics, facilitating a direct comparison to theory. - Studies of large samples of massive stars in our Galaxy and the Magellanic Clouds have unveiled new types of interaction products, providing critical constraints on the mass transfer phase and the formation of compact objects. - The direct detection of gravitational waves has revolutionized the study of stellar mass compact objects, providing a new window to study massive star evolution. Their formation processes are, however, still unclear. The known sample of compact object mergers will grow by orders of magnitude in the coming decade, turning into the best understood astrophysical population.

en astro-ph.SR, astro-ph.GA
S2 Open Access 2022
Quality and Safety Considerations in Stereotactic Radiosurgery and Stereotactic Body Radiation Therapy: An ASTRO Safety White Paper Update.

I. Das, S. Dawes, M. Dominello et al.

PURPOSE This updated report on stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT) is part of a series of consensus-based white papers previously published addressing patient safety. Since the first white papers were published, SRS and SBRT technology and procedures have progressed significantly such that these procedures are now more commonly used. The complexity and sub-millimeter accuracy, and delivery of a higher dose per fraction requires an emphasis on best practices for technical, dosimetric, and quality assurance (QA). Therefore, quality and patient safety considerations for these techniques remain an important area of focus. METHODS The American Society for Radiation Oncology (ASTRO) convened a task force to assess the original SRS/SBRT white paper and update content where appropriate. Recommendations were created using a consensus-building methodology and task force members indicated their level of agreement based on a 5-point Likert scale, from "strongly agree" to "strongly disagree." A prespecified threshold of ≥75% of raters who select "strongly agree" or "agree" indicated consensus. SUMMARY This white paper builds on the previous version and uses other guidance documents to broadly address SRS and SBRT delivery, primarily focusing on processes related to quality and safety. SRS and SBRT require a team-based approach, staffed by appropriately trained and credentialed specialists as well as significant personnel resources, specialized technology, and implementation time. A thorough feasibility analysis of resources is required to achieve the clinical and technical goals and thoroughly discussed with all personnel prior to undertaking new disease sites. A comprehensive QA program must be developed, using established treatment guidelines, to ensure SRS and SBRT are performed in a safe and effective manner. Patient safety in SRS/SBRT is everyone's responsibility and professional organizations, regulators, vendors, and end-users must demonstrate a clear commitment to working together to ensure the highest levels of safety.

26 sitasi en Medicine
S2 Open Access 2021
Radiation Therapy for Small-Cell Lung Cancer: ASCO Guideline Endorsement of an ASTRO Guideline.

M. Daly, Nofisat Ismaila, R. Decker et al.

PURPOSE The American Society for Radiation Oncology (ASTRO) produced an evidence-based guideline on radiation therapy (RT) for small-cell lung cancer (SCLC). Because of the relevance of this topic to ASCO membership, ASCO reviewed the guideline, applying a set of procedures and policies used to critically examine guidelines developed by other organizations. METHODS The ASTRO guideline on RT for SCLC was reviewed for developmental rigor by methodologists. Then, an ASCO Expert Panel reviewed the content and the recommendations. RESULTS The ASCO Expert Panel determined that the recommendations from ASTRO guideline on RT for SCLC, published in June 2020, are clear, thorough, and based upon the most relevant scientific evidence. ASCO endorsed ASTRO guideline on RT for SCLC with a few discussion points. RECOMMENDATIONS Recommendations addressed thoracic radiotherapy for limited-stage SCLC, role of stereotactic body radiotherapy in stage I or II node-negative SCLC, prophylactic cranial radiotherapy, and thoracic consolidation for extensive-stage SCLC.Additional information is available at www.asco.org/thoracic-cancer-guidelines.

49 sitasi en Medicine
S2 Open Access 2022
ASTRO's Framework for Radiopharmaceutical Therapy Curriculum Development for Trainees.

A. Kiess, R. Hobbs, B. Bednarz et al.

In 2017, the ASTRO Board of Directors prioritized radiopharmaceutical therapy (RPT) as a leading area for new therapeutic development, and the ASTRO RPT Workgroup was created. Herein the Workgroup has developed a framework for RPT curriculum development upon which education leaders can build to integrate this modality into radiation oncology resident education. Through this effort, the Workgroup aims to provide a guide to ensure robust training in an emerging therapeutic area within the context of existing radiation oncology training in radiation biology, medical physics, and clinical radiation oncology. The framework first determines the core RPT knowledge required to select patients, prescribe, safely administer, and manage related adverse events. Then, it defines the most important topics for preparing residents for clinical RPT planning and delivery. This framework is designed as a tool to supplement the current training that exists for radiation oncology residents. The final document was approved by the ASTRO Board of Directors in the Fall of 2021.

12 sitasi en Medicine
S2 Open Access 2020
Advanced Prostate Cancer: AUA/ASTRO/SUO Guideline PART I.

W. Lowrance, R. Breau, Roger Chou et al.

PURPOSE The summary presented herein represents Part I of the two-part series dedicated to Advanced Prostate Cancer: AUA/ASTRO/SUO Guideline discussing prognostic and treatment recommendations for patients with biochemical recurrence without metastatic disease after exhaustion of local treatment options as well as those with metastatic hormone-sensitive prostate cancer. Please refer to Part II for discussion of the management of castration-resistant disease. MATERIALS AND METHODS The systematic review utilized to inform this guideline was conducted by an independent methodological consultant. A research librarian conducted searches in Ovid MEDLINE (1998 to January Week 5 2019), Cochrane Central Register of Controlled Trials (through December 2018), and Cochrane Database of Systematic Reviews (2005 through February 6, 2019). An updated search was conducted prior to publication through January 20, 2020. The methodology team supplemented searches of electronic databases with the studies included in the prior AUA review and by reviewing reference lists of relevant articles. RESULTS The Advanced Prostate Cancer Panel created evidence- and consensus-based guideline statements to aid clinicians in the management of patients with advanced prostate cancer. Such statements are summarized in figure 1 and detailed herein. CONCLUSIONS This guideline attempts to improve a clinician's ability to treat patients diagnosed with advanced prostate cancer. Continued research and publication of high-quality evidence from future trials will be essential to improve the level of care for these patients.

76 sitasi en Medicine
S2 Open Access 2022
Astro-mT5: Entity Extraction from Astrophysics Literature using mT5 Language Model

Madhusudan Ghosh, Payel Santra, SK Asif Iqbal et al.

Scientific research requires reading and extracting relevant information from existing scientific literature in an effective way. To gain insights over a collection of such scientific documents, extraction of entities and recognizing their types is considered to be one of the important tasks. Numerous studies have been conducted in this area of research. In our study, we introduce a framework for entity recognition and identification of NASA astrophysics dataset, which was published as a part of the DEAL SharedTask. We use a pre-trained multilingual model, based on a natural language processing framework for the given sequence labeling tasks. Experiments show that our model, Astro-mT5, out-performs the existing baseline in astrophysics related information extraction.

S2 Open Access 2022
K-ASTRO: Structure-Aware Adaptation of LLMs for Code Vulnerability Detection

Yifan Zhang, Junwen Yang, Huihui Dong et al.

Large Language Models (LLMs) are transforming software engineering tasks, including code vulnerability detection-a critical area of software security. However, existing methods often rely on resource-intensive models or graph-based techniques, limiting their accessibility and practicality. This paper introduces K-ASTRO, a lightweight Transformer model that combines semantic embeddings from LLMs with structural features of Abstract Syntax Trees (ASTs) to improve both efficiency and accuracy in code vulnerability detection. Our approach introduces an AST-based augmentation technique inspired by mutation testing, a structure-aware attention mechanism that incorporates augmented AST features, and a joint adaptation pipeline to unify code semantics and syntax. Experimental results on three large-scale datasets, including BigVul, DiverseVul, and PrimeVul-demonstrate state-of-the-art performance while enabling rapid inference on CPUs with minimal training time. By offering a scalable, interpretable, and efficient solution, K-ASTRO bridges the gap between LLM advancements and practical software vulnerability detection, providing open-sourced tools to foster further research.

5 sitasi en Computer Science
S2 Open Access 2022
Astro-COLIBRI 2—An Advanced Platform for Real-Time Multi-Messenger Discoveries

P. Reichherzer, F. Schüssler, V. Lefranc et al.

The study of flaring astrophysical events in the multi-messenger approach requires instantaneous follow-up observations to better understand the nature of these events through complementary observational data. We present Astro-COLIBRI as a platform that integrates specific tools in the real-time multi-messenger ecosystem. The Astro-COLIBRI platform bundles and evaluates alerts about transients from various channels. It further automates the coordination of follow-up observations by providing and linking detailed information through its comprehensible graphical user interface. We present the functionalities with documented examples of Astro-COLIBRI usage through the community since its public release in August 2021. We highlight the use cases of Astro-COLIBRI for planning follow-up observations by professional and amateur astronomers, as well as checking predictions from theoretical models.

4 sitasi en Physics

Halaman 11 dari 63399