ADF95: Tool for automatic differentiation of a FORTRAN code designed for large numbers of independent variables

ADF95 is a tool to automatically calculate numerical first derivatives for any mathematical expression as a function of user defined independent variables. Accuracy of derivatives is achieved within machine precision. ADF95 may be applied to any FORTRAN 77/90/95 conforming code and requires minimal changes by the user. It provides a new derived data type that holds the value and derivatives and applies forward differencing by overloading all FORTRAN operators and intrinsic functions. An efficient indexing technique leads to a reduced memory usage and a substantially increased performance gain over other available tools with operator overloading. This gain is especially pronounced for sparse systems with large number of independent variables. A wide class of numerical simulations, e.g., those employing implicit solvers, can profit from ADF95.Comment: 24 pages, 2 figures, 4 tables, accepted in Computer Physics Communication

Thermonukleares Brennen und Mischen mit einer zeitabhängigen Konvektionstheorie in massereichen Population-III-Sternen

Die erste Generation von Sternen im Universum, die hypothetischen Population-III-Sterne, sollten sich aus reinem Wasserstoff-Helium-Gas frei von schweren Elementen gebildet haben. Die (quasi-)hydrostatische Entwicklung dieser Sterne wird im Massenbereich 15 Sonnenmassen bis 150 Sonnenmassen untersucht, angefangen von der Vorhauptreihe bis zum Ende des Hauptreihenstadiums. Wegen der anfaenglichen Abwesenheit von CNO-Elementen sowie der geringen Effizienz des pp-Brennens erreichen alle massereichen Population-III-Sterne die Hauptreihe im Vergleich zu 'normalen' Sternen als deutlich kompaktere und heissere Objekte. Population-III-Sterne mit Massen oberhalb von 30 Sonnenmassen kontrahieren bis zu Zentraltemperaturen von 100 Millionen Kelvin, produzieren im Drei-Alpha-Prozess Kohlenstoff und lassen sich im Modus des heissen CNO-Brennens auf der Hauptreihe nieder. Population-III-Sterne im Bereich 15 Sonnenmassen bis 30 Sonnenmassen erreichen die Hauptreihe im pp-Brennen, doch uebernimmt auch hier der CNO-Zyklus noch im Hauptreihenstadium die Energieproduktion. Die hohe Temperatur dieser Sterne fuehrt zur Koppelung der konvektiven Mischungszeitskala mit den Zeitskalen der Protoneneinfaenge und der Beta-Zerfaelle im CNO-Zyklus. Das Mischen kann nicht mehr als instantan innerhalb der Konvektionszonen angenommen werden. Ein neu entwickelter Sternentwicklungscode, der auf dem Softwarepaket LIMEX aufsetzt, integriert die Sternaufbaugleichungen zusammen mit einem zeitabhaengigen Kernreaktionsnetzwerk, zeitabhaengigem Mischen und einer zeitabhaengigen Konvektionstheorie erstmals vollstaendig gekoppelt und implizit. Die verbesserte Modellierung der Kernreaktionen und des Mischens wirkt sich nur in der raeumlichen Verteilung der CNO-Elemente aus, die 10 Prozent bis 20 Prozent von einer homogenen Durchmischung abweicht. Die verwendete zeitabhaengige Konvektionstheorie fuehrt in allen Modellen zu groesseren Konvektionszonen im Vergleich zu bestehe

Space and Ground Based Pulsation Data of Eta Bootis Explained with Stellar Models Including Turbulence

The space telescope MOST is now providing us with extremely accurate low frequency p-mode oscillation data for the star Eta Boo. We demonstrate in this paper that these data, when combined with ground based measurements of the high frequency p-mode spectrum, can be reproduced with stellar models that include the effects of turbulence in their outer layers. Without turbulence, the l=0 modes of our models deviate from either the ground based or the space data by about 1.5-4.0 micro Hz. This discrepancy can be completely removed by including turbulence in the models and we can exactly match 12 out of 13 MOST frequencies that we identified as l=0 modes in addition to 13 out of 21 ground based frequencies within their observational 2 sigma tolerances. The better agreement between model frequencies and observed ones depends for the most part on the turbulent kinetic energy which was taken from a 3D convection simulation for the Sun.Comment: 13 pages, 7 figures, ApJ in pres

Core Overshoot: An Improved Treatment and Constraints from Seismic Data

We present a comprehensive set of stellar evolution models for Procyon A in an effort to guide future measurements of both traditional stellar parameters and seismic frequencies towards constraining the amount of core overshoot in Procyon A and possibly other stars. Current observational measurements of Procyon A when combined with traditional stellar modeling only place a large upper limit on overshoot of alphaOV < 1.1. By carrying out a detailed pulsation analysis, we further demonstrate, how p- and g-mode averaged spacings can be used to gain better estimates of the core size. For both p- and g-modes, the frequency spacings for models without overshoot are clearly separated from the models with overshoot. In addition, measurements of the l=0 averaged small p-mode spacings could be used to establish Procyon A's evolutionary stage. For a fixed implementation of overshoot and under favorable circumstances, the g-mode spacings can be used to determine the overshoot extent to an accuracy of +-0.05 Hp. However, we stress that considerable confusion is added due to the unknown treatment of the overshoot region. This ambiguity might be removed by analyzing many different stars. A simple non-local convection theory developed by Kuhfuss is implemented in our stellar evolution code and contrasted with the traditional approaches. We show that this theory supports a moderate increase of the amount of convective overshoot with stellar mass of Delta(alphaOV) = +0.10 between 1.5 Msun and 15 Msun. This theory places an upper limit on Procyon A's core overshoot extent of ~0.4 Hp which matches the limit imposed by Roxburgh's integral criterion.Comment: 45 pages, 26 figures, accepted in Ap

Current Issues in Asteroseismology

In this contribution we briefly review some of the current issues and promises for the future by asteroseismology. We are entering a new phase in this field driven by the wealth of data that has been collected and data that will soon be available for asteroseismology across the HR Diagram. Major difficulties in the descriptions of stellar interiors that arose in the second half of the 20th century may now be in part addressed and solved (this is the expectation!) by asteroseismology with unprecedented precision. In this contribution we list some of the key open questions in stellar physics, the seismic data we expect to collect in the near future, and some techniques that will provide the tools to connect data and models.Comment: 9 pages, 2 figures - to appear in Helioseismology, Asteroseismology and MHD Connections, (Eds) L. Gizon et al., Journal of Physics Conference Series, 2008 [Revision 1 - english; Revision 2 - references

The recovery of European freshwater biodiversity has come to a halt

Owing to a long history of anthropogenic pressures, freshwater ecosystems are among the most vulnerable to biodiversity loss1. Mitigation measures, including wastewater treatment and hydromorphological restoration, have aimed to improve environmental quality and foster the recovery of freshwater biodiversity2. Here, using 1,816 time series of freshwater invertebrate communities collected across 22 European countries between 1968 and 2020, we quantified temporal trends in taxonomic and functional diversity and their responses to environmental pressures and gradients. We observed overall increases in taxon richness (0.73% per year), functional richness (2.4% per year) and abundance (1.17% per year). However, these increases primarily occurred before the 2010s, and have since plateaued. Freshwater communities downstream of dams, urban areas and cropland were less likely to experience recovery. Communities at sites with faster rates of warming had fewer gains in taxon richness, functional richness and abundance. Although biodiversity gains in the 1990s and 2000s probably reflect the effectiveness of water-quality improvements and restoration projects, the decelerating trajectory in the 2010s suggests that the current measures offer diminishing returns. Given new and persistent pressures on freshwater ecosystems, including emerging pollutants, climate change and the spread of invasive species, we call for additional mitigation to revive the recovery of freshwater biodiversity.N. Kaffenberger helped with initial data compilation. Funding for authors and data collection and processing was provided by the EU Horizon 2020 project eLTER PLUS (grant agreement no. 871128); the German Federal Ministry of Education and Research (BMBF; 033W034A); the German Research Foundation (DFG FZT 118, 202548816); Czech Republic project no. P505-20-17305S; the Leibniz Competition (J45/2018, P74/2018); the Spanish Ministerio de Economía, Industria y Competitividad—Agencia Estatal de Investigación and the European Regional Development Fund (MECODISPER project CTM 2017-89295-P); Ramón y Cajal contracts and the project funded by the Spanish Ministry of Science and Innovation (RYC2019-027446-I, RYC2020-029829-I, PID2020-115830GB-100); the Danish Environment Agency; the Norwegian Environment Agency; SOMINCOR—Lundin mining & FCT—Fundação para a Ciência e Tecnologia, Portugal; the Swedish University of Agricultural Sciences; the Swiss National Science Foundation (grant PP00P3_179089); the EU LIFE programme (DIVAQUA project, LIFE18 NAT/ES/000121); the UK Natural Environment Research Council (GLiTRS project NE/V006886/1 and NE/R016429/1 as part of the UK-SCAPE programme); the Autonomous Province of Bolzano (Italy); and the Estonian Research Council (grant no. PRG1266), Estonian National Program ‘Humanitarian and natural science collections’. The Environment Agency of England, the Scottish Environmental Protection Agency and Natural Resources Wales provided publicly available data. We acknowledge the members of the Flanders Environment Agency for providing data. This article is a contribution of the Alliance for Freshwater Life (www.allianceforfreshwaterlife.org).Peer reviewe

Autologous stem cell transplantation in multiple myeloma patients: utilization patterns and hospital effects

Evidence on volume outcome associations for autologous stem cell transplantation (ASCT) in multiple myeloma (MM) is limited. We investigated ASCT utilization patterns and volume outcome associations in the German National Registry for Stem Cell Transplants (DRST). MM patients with an upfront ASCT between 1998 and 2014 registered in the DRST were included. ASCT utilization increased strongly from 6% to 17% between 1999 and 2013 with the largest increase for patients aged 60-64 years (8-34%). The mean number of ASCTs conducted in the hospitals per year varied (quintiles, Q1:0.0-8.2 to Q5:31.0-102.7). Center volume was not associated with survival after upfront ASCT (lowest vs. highest center volume, hazard ratios and 95% confidence intervals: 0.95 (0.76-1.18),p = 0.92). Our findings may reflect a high standard of care and degree of specialization of centers performing ASCT for MM in Germany

From transplant to novel cellular therapies in multiple myeloma: EMN guidelines and future perspectives.

Survival of myeloma patients has greatly improved with the use of autologous stem cell transplantation and novel agents, such as proteasome inhibitors, immunomodulatory drugs and monoclonal antibodies. Compared to bortezomib- and lenalidomide-based regimens alone, the addition of high-dose melphalan followed by autologous transplantation significantly improves progression-free survival; although an overall survival benefit was not observed in all trials. Moreover, follow-up of recent trials is still too short to show any difference in survival. In the light of these findings, novel agent-based induction followed by autologous transplantation is considered the standard upfront treatment for eligible patients (level of evidence: 1A). Post-transplant consolidation and maintenance treatment can further improve patient outcome (1A). The availability of several novel agents has led to the development of multiple combination regimens as salvage treatment options. In this context, the role of salvage autologous transplantation and allotransplant have not been extensively evaluated. In case of prolonged remission after upfront autologous transplantation, another autologous transplantation at relapse can be considered (2B). Patients who experience early relapse and/or have high-risk features have a poor prognosis and may be considered as candidates for clinical trials that - in young and fit patients - may also include an allograft in combination with novel agents (2B). Ongoing studies are evaluating the role of novel cellular therapies, such as inclusion of antibody-based triplets and quadruplets and Chimeric Antigen Receptor-T cells: despite preliminary encouraging results, longer follow-up and larger patient numbers are needed before their clinical use can be widely recommended