Actinide R-Process Chronometers and β-Delayed Fission

1984 ◽  
pp. 389-396 ◽  
Author(s):  
F.-K. Thielemann
Keyword(s):  
R Process

Distribution of R- and S-Process Elements in the Galactic Halo

1988 ◽  
Vol 132 ◽  
pp. 501-506
Author(s):  
C. Sneden ◽  
C. A. Pilachowski ◽  
K. K. Gilroy ◽  
J. J. Cowan
Keyword(s):  
Heavy Element ◽  
Galactic Halo ◽  
Low Noise ◽  
Heavy Elements ◽  
Process Synthesis ◽  
Element Abundances ◽  
Halo Stars ◽  
Abundance Patterns ◽  
R Process ◽  
Process Elements

Current observational results for the abundances of the very heavy elements (Z>30) in Population II halo stars are reviewed. New high resolution, low noise spectra of many of these extremely metal-poor stars reveal general consistency in their overall abundance patterns. Below Galactic metallicities of [Fe/H] Ã −2, all of the very heavy elements were manufactured almost exclusively in r-process synthesis events. However, there is considerable star-to-star scatter in the overall level of very heavy element abundances, indicating the influence of local supernovas on element production in the very early, unmixed Galactic halo. The s-process appears to contribute substantially to stellar abundances only in stars more metal-rich than [Fe/H] Ã −2.

Nuclear Processes Related to the Ap Stars and the Heaviest Chemical Elements

1976 ◽  
Vol 32 ◽  
pp. 169-182
Author(s):  
B. Kuchowicz
Keyword(s):  
Nuclear Physics ◽  
Nuclear Reactions ◽  
Chemical Elements ◽  
Fission Products ◽  
Abundance Pattern ◽  
Isotopic Shifts ◽  
Processed Material ◽  
R Process ◽  
Ap Stars ◽  
Nuclear Processes

SummaryIsotopic shifts in the lines of the heavy elements in Ap stars, and the characteristic abundance pattern of these elements point to the fact that we are observing mainly the products of rapid neutron capture. The peculiar A stars may be treated as the show windows for the products of a recent r-process in their neighbourhood. This process can be located either in Supernovae exploding in a binary system in which the present Ap stars were secondaries, or in Supernovae exploding in young clusters. Secondary processes, e.g. spontaneous fission or nuclear reactions with highly abundant fission products, may occur further with the r-processed material in the surface of the Ap stars. The role of these stars to the theory of nucleosynthesis and to nuclear physics is emphasized.

scholarly journals Fission fragment distributions and their impact on the r -process nucleosynthesis in neutron star mergers

2021 ◽  
Vol 103 (2) ◽  
Author(s):  
J.-F. Lemaître ◽  
S. Goriely ◽  
A. Bauswein ◽  
H.-T. Janka
Keyword(s):  
Neutron Star ◽  
Fission Fragment ◽  
R Process

The origin of r-process elements

Science ◽  
2021 ◽  
Vol 371 (6532) ◽  
pp. 901.18-903
Author(s):  
Keith T. Smith
Keyword(s):  
R Process ◽  
Process Elements

PP469 From Theory To Practice: Which Value Framework Is Applied For Onco-Hematology Therapies In Italy? A 5-year Retrospective Analysis

2020 ◽  
Vol 36 (S1) ◽  
pp. 37-37
Author(s):  
Americo Cicchetti ◽  
Rossella Di Bidino ◽  
Entela Xoxi ◽  
Irene Luccarini ◽  
Alessia Brigido
Keyword(s):  
Real World ◽  
Ad Hoc ◽  
Grey Literature ◽  
National Level ◽  
Pharmaceutical Products ◽  
European Medicines Agency ◽  
The Real ◽  
R Process ◽  
The One ◽  
The Impact

IntroductionDifferent value frameworks (VFs) have been proposed in order to translate available evidence on risk-benefit profiles of new treatments into Pricing & Reimbursement (P&R) decisions. However limited evidence is available on the impact of their implementation. It's relevant to distinguish among VFs proposed by scientific societies and providers, which usually are applicable to all treatments, and VFs elaborated by regulatory agencies and health technology assessment (HTA), which focused on specific therapeutic areas. Such heterogeneity in VFs has significant implications in terms of value dimension considered and criteria adopted to define or support a price decision.MethodsA literature research was conducted to identify already proposed or adopted VF for onco-hematology treatments. Both scientific and grey literature were investigated. Then, an ad hoc data collection was conducted for multiple myeloma; breast, prostate and urothelial cancer; and Non Small Cell Lung Cancer (NSCLC) therapies. Pharmaceutical products authorized by European Medicines Agency from January 2014 till December 2019 were identified. Primary sources of data were European Public Assessment Reports and P&R decision taken by the Italian Medicines Agency (AIFA) till September 2019.ResultsThe analysis allowed to define a taxonomy to distinguish categories of VF relevant to onco-hematological treatments. We identified the “real-world” VF that emerged given past P&R decisions taken at the Italian level. Data was collected both for clinical and economical outcomes/indicators, as well as decisions taken on innovativeness of therapies. Relevant differences emerge between the real world value framework and the one that should be applied given the normative framework of the Italian Health System.ConclusionsThe value framework that emerged from the analysis addressed issues of specific aspects of onco-hematological treatments which emerged during an ad hoc analysis conducted on treatment authorized in the last 5 years. The perspective adopted to elaborate the VF was the one of an HTA agency responsible for P&R decisions at a national level. Furthermore, comparing a real-world value framework with the one based on the general criteria defined by the national legislation, our analysis allowed identification of the most critical point of the current national P&R process in terms ofsustainability of current and future therapies as advance therapies and agnostic-tumor therapies.

scholarly journals 13,14B(n, γ) via Coulomb Dissociation for Nucleosynthesis towards the r-Process

2014 ◽  
Vol 120 ◽  
pp. 197-200 ◽  
Author(s):  
S.G. Altstadt ◽  
T. Adachi ◽  
Y. Aksyutina ◽  
J. Alcantara ◽  
H. Alvarez-Pol ◽  
...  
Keyword(s):  
Coulomb Dissociation ◽  
R Process

scholarly journals Price and reimbursement of advanced therapeutic medicinal products in Europe: are assessment and appraisal diverging from expert recommendations?

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Virginia Ronco ◽  
Myriam Dilecce ◽  
Elena Lanati ◽  
Pier Luigi Canonico ◽  
Claudio Jommi
Keyword(s):  
Selection Process ◽  
Grey Literature ◽  
Primary Objective ◽  
Medicinal Products ◽  
Health Authorities ◽  
Advanced Therapy ◽  
Additional Funding ◽  
Managed Entry Agreements ◽  
R Process ◽  
Expert Recommendations

Abstract Background Advanced therapy medicinal products (ATMPs) represent an important cornerstone for innovation in healthcare. However, uncertainty on the value, the high average cost per patient and their one-shot nature has raised a debate on their assessment and appraisal process for pricing and reimbursement (P&R) purposes. This debate led experts providing for recommendations on this topic. Our primary objective is to investigate the ATMPs P&R process in the main five European countries and to understand if this process is consistent with published P&R expert recommendations. We also investigated the current ATMP pipelines to understand if future ATMPs will create challenges for their P&R process. Methods P&R framework for ATMPs in the European Major five (EU5) countries was investigated through a literature search on PubMed, institutional websites of National Health Authorities and grey literature. The ATMPs pipeline database was populated from a clinical trial database (clinicaltrials.gov), relying on inclusion and exclusion criteria retrieved from the literature. Results Reimbursement status of ATMPs is different across the EU5 countries, with the exception of CAR-Ts which are reimbursed in all countries. Standard P&R process in place for other medicinal products is extended to ATMPs, with the exception of some cases in Germany. List prices, where available, are high and, tend to be aligned across countries. Outcome-based Managed Entry Agreements (MEAs) have been extensively used for ATMPs. Extra-funds for hospitals managing ATMPs were provided only in Germany and, as additional fund per episode, in France. The accreditation process of hospitals for ATMPs management was in most countries managed by the national authorities. As far as ATMPs pipeline is concerned, ATMPs in development are mostly targeting non-rare diseases. Conclusions Expert recommendations for ATMPs P&R were partially applied: the role of outcome-based MEAs has increased and the selection process of the centres authorized to use these treatments has been enhanced; additional funding for ATMPs management to accredited centres has not been completely considered and annuity payment and broader perspective in cost considerations are far from being put in place. These recommendations should be considered for future P&R negotiations to pursue rational resource allocation and deal with budget constraints.

scholarly journals 10. General Discussion

1960 ◽  
Vol 10 ◽  
pp. 677-679 ◽  
Keyword(s):  
Yield Curve ◽  
Fission Products ◽  
Heavy Elements ◽  
Sikhote Alin ◽  
Heavy Nuclei ◽  
Fission Yield ◽  
Element Abundances ◽  
The Earth ◽  
R Process ◽  
Nova Outburst

1. p. SELINOV: Anomalous abundances of Te and Xe isotopes in meteorites and in the Earth permit us to draw some conclusions concerning the age of uranium and the processes of nucleogenesis. According to the estimate by Hoyle the amount of 254Cf disintegrated during a super-nova outburst is of the order of io29 g or io~4 of the stellar mass. According to the fission-yield curve the isotopes of Te comprise about 1 % of the mass of fission products. The abundances of Te 128-131 are anomalously high, due to the fission of heavy nuclei. The element abundances do not permit us to draw any conclusions about the r-process. The isotopes of Te and Xe with even mass numbers give evidence in favour of the r-process (anomalously high abundances). But the amount of Te in meteorites and in Earth is about 1000 times less than it should be if formed during the outburst. The Sikhote- Alin meteorite shows the same anomaly. We may conclude that the heavy elements of the solar system have been formed not in a single super-nova outburst, but as a result of mixing from the totality of outbursts. According to Hoyle, this gives a definite estimate for the age of uranium.

scholarly journals The AMBRE Project: r-process elements in the Milky Way thin and thick discs

2018 ◽  
Vol 619 ◽  
pp. A143 ◽  
Author(s):  
G. Guiglion ◽  
P. de Laverny ◽  
A. Recio-Blanco ◽  
N. Prantzos
Keyword(s):  
Chemical Evolution ◽  
Milky Way ◽  
Element Abundances ◽  
Thick Disc ◽  
Thin Disc ◽  
Solar Metallicity ◽  
R Process ◽  
Process Elements ◽  
Process Element ◽  
The Eu

Context. The chemical evolution of neutron capture elements in the Milky Way disc is still a matter of debate. There is a lack of statistically significant catalogues of such element abundances, especially those of the r-process. Aims. We aim to understand the chemical evolution of r-process elements in Milky Way disc. We focus on three pure r-process elements Eu, Gd, and Dy. We also consider a pure s-process element, Ba, in order to disentangle the different nucleosynthesis processes. Methods. We take advantage of high-resolution FEROS, HARPS, and UVES spectra from the ESO archive in order to perform a homogeneous analysis on 6500 FGK Milky Way stars. The chemical analysis is performed thanks to the automatic optimization pipeline GAUGUIN. We present abundances of Ba (5057 stars), Eu (6268 stars), Gd (5431 stars), and Dy (5479 stars). Based on the [α/Fe] ratio determined previously by the AMBRE Project, we chemically characterize the thin and the thick discs, and a metal-rich α-rich population. Results. First, we find that the [Eu/Fe] ratio follows a continuous sequence from the thin disc to the thick disc as a function of the metallicity. Second, in thick disc stars, the [Eu/Ba] ratio is found to be constant, while the [Gd/Ba] and [Dy/Ba] ratios decrease as a function of the metallicity. These observations clearly indicate a different nucleosynthesis history in the thick disc between Eu and Gd–Dy. The [r/Fe] ratio in the thin disc is roughly around +0.1 dex at solar metallicity, which is not the case for Ba. We also find that the α-rich metal-rich stars are also enriched in r-process elements (like thick disc stars), but their [Ba/Fe] is very different from thick disc stars. Finally, we find that the [r/α] ratio tends to decrease with metallicity, indicating that supernovae of different properties probably contribute differently to the synthesis of r-process elements and α-elements. Conclusions. We provide average abundance trends for [Ba/Fe] and [Eu/Fe] with rather small dispersions, and for the first time for [Gd/Fe] and [Dy/Fe]. This data may help to constrain chemical evolution models of Milky Way r- and s-process elements and the yields of massive stars. We emphasize that including yields of neutron-star or black hole mergers is now crucial if we want to quantitatively compare observations to Galactic chemical evolution models.

scholarly journals Nuclear burning in collapsar accretion discs

2020 ◽  
Vol 499 (3) ◽  
pp. 4097-4113 ◽  
Author(s):  
Yossef Zenati ◽  
Daniel M Siegel ◽  
Brian D Metzger ◽  
Hagai B Perets
Keyword(s):  
Angular Momentum ◽  
Gamma Ray ◽  
Nuclear Reactions ◽  
Reaction Network ◽  
Accretion Discs ◽  
Late Time ◽  
Rotating Stars ◽  
Stellar Envelope ◽  
Nuclear Burning ◽  
R Process

ABSTRACT The core collapse of massive, rapidly-rotating stars are thought to be the progenitors of long-duration gamma-ray bursts (GRB) and their associated hyperenergetic supernovae (SNe). At early times after the collapse, relatively low angular momentum material from the infalling stellar envelope will circularize into an accretion disc located just outside the black hole horizon, resulting in high accretion rates necessary to power a GRB jet. Temperatures in the disc mid-plane at these small radii are sufficiently high to dissociate nuclei, while outflows from the disc can be neutron-rich and may synthesize r-process nuclei. However, at later times, and for high progenitor angular momentum, the outer layers of the stellar envelope can circularize at larger radii ≳ 107 cm, where nuclear reactions can take place in the disc mid-plane (e.g. 4He + 16O → 20Ne + γ). Here we explore the effects of nuclear burning on collapsar accretion discs and their outflows by means of hydrodynamical α-viscosity torus simulations coupled to a 19-isotope nuclear reaction network, which are designed to mimic the late infall epochs in collapsar evolution when the viscous time of the torus has become comparable to the envelope fall-back time. Our results address several key questions, such as the conditions for quiescent burning and accretion versus detonation and the generation of 56Ni in disc outflows, which we show could contribute significantly to powering GRB SNe. Being located in the slowest, innermost layers of the ejecta, the latter could provide the radioactive heating source necessary to make the spectral signatures of r-process elements visible in late-time GRB-SNe spectra.

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