Functionally Dissociable Influences on Learning Rate in a Dynamic Environment

Maintaining accurate beliefs in a changing environment requires dynamically adapting the rate at which one learns from new experiences. Beliefs should be stable in the face of noisy data but malleable in periods of change or uncertainty. Here we used computational modeling, psychophysics, and fMRI to show that adaptive learning is not a unitary phenomenon in the brain. Rather, it can be decomposed into three computationally and neuroanatomically distinct factors that were evident in human subjects performing a spatial-prediction task: (1) surprise-driven belief updating, related to BOLD activity in visual cortex; (2) uncertainty-driven belief updating, related to anterior prefrontal and parietal activity; and (3) reward-driven belief updating, a context-inappropriate behavioral tendency related to activity in ventral striatum. These distinct factors converged in a core system governing adaptive learning. This system, which included dorsomedial frontal cortex, responded to all three factors and predicted belief updating both across trials and across individuals

Knowledge, Beliefs, and Decisions of Pregnant Australian Women Concerning Donation and Storage of Umbilical Cord Blood: A Population‐Based Survey

postprintBackground: Many women giving birth in Australian hospitals can choose to donate their child’s umbilical cord blood to a public cord blood bank or pay to store it privately. We conducted a survey to determine the proportion and characteristics of pregnant women who are aware of umbilical cord blood (UCB) banking and who have considered and decided about this option. The survey also sought to ascertain information sources, knowledge and beliefs about UCB banking, and the effect of basic information about UCB on decisions. Methods: Researchers and/or hospital maternity staff distributed a survey with basic information about UCB banking to 1,873 women of at least 24 weeks gestation who were attending antenatal classes and hospital clinics in 14 Public and private maternity hospitals in New South Wales. Results: Most respondents (70.7%) were aware of UCB banking. Their main information sources were leaflets from hospital clinics, print media, antenatal classes, TV, radio, friends and relatives. Knowledge about UCB banking was patchy, and respondents overestimated the likelihood their child would need or benefit from UCB. Women who were undecided about UCB banking were younger, less educated or from ethnic or rural backgrounds. After providing basic information about UCB banking, the proportion of respondents who indicated they had decided whether or not to donate or store UCB more than doubled from 30.0% to 67.7%. Conclusions: Basic information for parents about UCB banking can affect planned decisions about UCB banking. Information should be accurate and balanced, should counter misconceptions, and should target specific groups. Keywords: Antenatal care; Health information; Blood banks; New South Wales, AustraliaNational Health and Medical Research Council of Australia. Grant Number: 51241

Knowledge, Beliefs, and Decisions of Pregnant Australian Women Concerning Donation and Storage of Umbilical Cord Blood: A Population‐Based Survey

Background: Many women giving birth in Australian hospitals can choose to donate their child’s umbilical cord blood to a public cord blood bank or pay to store it privately. We conducted a survey to determine the proportion and characteristics of pregnant women who are aware of umbilical cord blood (UCB) banking and who have considered and decided about this option. The survey also sought to ascertain information sources, knowledge and beliefs about UCB banking, and the effect of basic information about UCB on decisions. Methods: Researchers and/or hospital maternity staff distributed a survey with basic information about UCB banking to 1,873 women of at least 24 weeks gestation who were attending antenatal classes and hospital clinics in 14 Public and private maternity hospitals in New South Wales. Results: Most respondents (70.7%) were aware of UCB banking. Their main information sources were leaflets from hospital clinics, print media, antenatal classes, TV, radio, friends and relatives. Knowledge about UCB banking was patchy, and respondents overestimated the likelihood their child would need or benefit from UCB. Women who were undecided about UCB banking were younger, less educated or from ethnic or rural backgrounds. After providing basic information about UCB banking, the proportion of respondents who indicated they had decided whether or not to donate or store UCB more than doubled from 30.0% to 67.7%. Conclusions: Basic information for parents about UCB banking can affect planned decisions about UCB banking. Information should be accurate and balanced, should counter misconceptions, and should target specific groups. Keywords: Antenatal care; Health information; Blood banks; New South Wales, AustraliaNational Health and Medical Research Council of Australia. Grant Number: 51241

The Karlsruhe Astrophysical Database of Nucleosynthesis in Stars Project - Status and Prospects

The KADoNiS (Karlsruhe Astrophysical Database of Nucleosynthesis in Stars) project is an astrophysical online database for cross sections relevant for nucleosynthesis in the s process and the γ process. The s-process database (http://www.kadonis.org) was started in 2005 and is presently facing its 4th update (KADoNiS v1.0). The γ-process database (KADoNiS-p, http://www.kadonis.org/pprocess) was recently revised and re-launched in March 2013. Both databases are compilations for experimental cross sections with relevance to heavy ion nucleosynthesis. For the s process recommended Maxwellian averaged cross sections for kT=5-100 keV are given for more than 360 isotopes between 1H and 210Bi. For the γ-process database all available experimental data from (p, γ), (p, n), (p, α), (α, γ), (α, n), and (α, p) reactions between 70Ge and 209Bi in or close to the respective Gamow window were collected and can be compared to theoretical predictions. The aim of both databases is a quick and user-friendly access to the available data in the astrophysically relevant energy regions. © 2014 Elsevier Inc.Peer reviewe

Solving the stellar 62Ni problem with AMS

An accurate knowledge of the neutron capture cross sections of 62,63Ni is crucial since both isotopes take key positions which affect the whole reaction flow in the weak s process up to A=90. No experimental value for the 63Ni(n,gamma) cross section exists so far, and until recently the experimental values for 62Ni(n,gamma) at stellar temperatures (kT=30 keV) ranged between 12 and 37 mb. This latter discrepancy could now be solved by two activations with following AMS using the GAMS setup at the Munich tandem accelerator which are also in perfect agreement with a recent time-of-flight measurement. The resulting (preliminary) Maxwellian cross section at kT=30 keV was determined to be 30keV = 23.4 +/- 4.6 mb. Additionally, we have measured the 64Ni(gamma,n)63Ni cross section close to threshold. Photoactivations at 13.5 MeV, 11.4 MeV and 10.3 MeV were carried out with the ELBE accelerator at Forschungszentrum Dresden-Rossendorf. A first AMS measurement of the sample activated at 13.5 MeV revealed a cross section smaller by more than a factor of 2 compared to NON-SMOKER predictions.Comment: Proceedings of the 11th International Conference on Accelerator Mass Spectrometry in Rome, Sept. 14-19, 2008; to be published in Nucl. Instr. Meth.

Analgesic Effects of GpTx-1, PF-04856264 and CNV1014802 in a Mouse Model of NaV1.7-Mediated Pain

Loss-of-function mutations of NaV1.7 lead to congenital insensitivity to pain, a rare condition resulting in individuals who are otherwise normal except for the inability to sense pain, making pharmacological inhibition of NaV1.7 a promising therapeutic strategy for the treatment of pain. We characterized a novel mouse model of NaV1.7-mediated pain based on intraplantar injection of the scorpion toxin OD1, which is suitable for rapid in vivo profiling of NaV1.7 inhibitors. Intraplantar injection of OD1 caused spontaneous pain behaviors, which were reversed by co-injection with NaV1.7 inhibitors and significantly reduced in NaV1.7−/− mice. To validate the use of the model for profiling NaV1.7 inhibitors, we determined the NaV selectivity and tested the efficacy of the reported NaV1.7 inhibitors GpTx-1, PF-04856264 and CNV1014802 (raxatrigine). GpTx-1 selectively inhibited NaV1.7 and was effective when co-administered with OD1, but lacked efficacy when delivered systemically. PF-04856264 state-dependently and selectively inhibited NaV1.7 and significantly reduced OD1-induced spontaneous pain when delivered locally and systemically. CNV1014802 state-dependently, but non-selectively, inhibited NaV channels and was only effective in the OD1 model when delivered systemically. Our novel model of NaV1.7-mediated pain based on intraplantar injection of OD1 is thus suitable for the rapid in vivo characterization of the analgesic efficacy of NaV1.7 inhibitors

Massive stars as thermonuclear reactors and their explosions following core collapse

Nuclear reactions transform atomic nuclei inside stars. This is the process of stellar nucleosynthesis. The basic concepts of determining nuclear reaction rates inside stars are reviewed. How stars manage to burn their fuel so slowly most of the time are also considered. Stellar thermonuclear reactions involving protons in hydrostatic burning are discussed first. Then I discuss triple alpha reactions in the helium burning stage. Carbon and oxygen survive in red giant stars because of the nuclear structure of oxygen and neon. Further nuclear burning of carbon, neon, oxygen and silicon in quiescent conditions are discussed next. In the subsequent core-collapse phase, neutronization due to electron capture from the top of the Fermi sea in a degenerate core takes place. The expected signal of neutrinos from a nearby supernova is calculated. The supernova often explodes inside a dense circumstellar medium, which is established due to the progenitor star losing its outermost envelope in a stellar wind or mass transfer in a binary system. The nature of the circumstellar medium and the ejecta of the supernova and their dynamics are revealed by observations in the optical, IR, radio, and X-ray bands, and I discuss some of these observations and their interpretations.Comment: To be published in " Principles and Perspectives in Cosmochemistry" Lecture Notes on Kodai School on Synthesis of Elements in Stars; ed. by Aruna Goswami & Eswar Reddy, Springer Verlag, 2009. Contains 21 figure