Search results for "reaktiot"

Isomeric fission yield ratios for odd-mass Cd and In isotopes using the Phase-Imaging Ion-Cyclotron-Resonance technique

2018

Isomeric yield ratios for the odd-$A$ isotopes of $^{119-127}$Cd and $^{119-127}$In from 25-MeV proton-induced fission on natural uranium have been measured at the JYFLTRAP double Penning trap, by employing the Phase-Imaging Ion-Cyclotron-Resonance technique. With the significantly improved mass resolution of this novel method isomeric states separated by 140 keV from the ground state, and with half-lives of the order of 500 ms, could be resolved. This opens the door for obtaining new information on low-lying isomers, of importance for nuclear structure, fission and astrophysics. In the present work the experimental isomeric yield ratios are used for the estimation of the root-mean-square a…

Ethyl-eicosapentaenoic acid and carnosine supplementation's effects on cognitive, behavioural and psychophysiological parameters on healthy young sub…

2007

Common and separable behavioral and neural mechanisms underlie the generalization of fear and disgust

2021

Generalization represents the transfer of a conditioned responses to stimuli that resemble the conditioned stimulus (CS). Previous studies on generalization of defensive avoidance responses have primarily focused on fear and have neglected disgust generalization, which represents a key pathological mechanism in some anxiety disorders. In the present study we examined common and distinct mechanisms of fear and disgust generalization by means of a fear or disgust multi-CS conditioning and generalization paradigm with concomitant event-related potential (ERPs) acquisition in n = 62 subjects. We demonstrate that compared to fear, disgust-relevant generalized stimuli (GS) elicited larger expecta…

In-beam spectroscopic studies of shape coexistence and collectivity in the neutron-deficientZ≈ 82 nuclei

2016

In the present paper we focus on studies of shape coexistence in even-mass nuclei in the neutron-deficient Pb region. They are based on experiments carried out using tagging techniques in the Accelerator Laboratory of the University of Jyväskylä, Finland. Excited states in many of these nuclei can only be accessed via fusion-evaporation reactions employing high-intensity stable-ion beams. The key features in these experiments are high selectivity, clean spectra and instrumentation that enables high count rates. We review three spectroscopic highlights in this region. peerReviewed

Progress on nuclear reaction rates affecting the stellar production of 26Al

2023

Abstract The radioisotope 26Al is a key observable for nucleosynthesis in the Galaxy and the environment of the early Solar System. To properly interpret the large variety of astronomical and meteoritic data, it is crucial to understand both the nuclear reactions involved in the production of 26Al in the relevant stellar sites and the physics of such sites. These range from the winds of low- and intermediate-mass asymptotic giant branch stars; to massive and very massive stars, both their Wolf–Rayet winds and their final core-collapse supernovae (CCSN); and the ejecta from novae, the explosions that occur on the surface of a white dwarf accreting material from a stellar companion. Several r…

Unraveling the Role of the Rh–ZrO2 Interface in the Water–Gas-Shift Reaction via a First-Principles Microkinetic Study

2018

The industrially important water–gas-shift (WGS) reaction is a complex network of competing elementary reactions in which the catalyst is a multicomponent system consisting of distinct domains. Herein, we have combined density functional theory calculations with microkinetic modeling to explore the active phase, kinetics, and reaction mechanism of the WGS over the Rh–ZrO2 interface. We have explicitly considered the support and metal and their interface and find that the Rh–ZrO2 interface is far more active toward WGS than Rh(111) facets, which are susceptible to CO poisoning. CO2 forming on the zirconia support rapidly transforms into formate. These findings demonstrate the central role of…

Iän, sukupuolen ja harjoittelun yhteys reaktionopeuteen mies- ja naisveteraaniurheilijoilla

2013

IÄN, SUKUPUOLEN JA HARJOITTELUN YHTEYS REAKTIONOPEUTEEN MIES - JA NAISVETERAANIURHEILIJOILLA Laura Vainio Pro gradu –tutkielma Gerontologia ja kansanterveys Jyväskylän yliopisto, liikuntatieteellinen tiedekunta, terveystieteiden laitos Kevät 2013 43 sivua, 1 liite Yksi ikääntymisen mukana tapahtuva toimintojen heikkeneminen ilmenee ärsykkeisiin reagoimisen ja reaktionopeuden hidastumisena. Mitä enemmän ikääntyvillä ihmisillä on nopeutta, kestävyyttä ja lihasvoimaa, sitä paremmin he suoriutuvat jokapäiväisistä arkiaskareista. Fyysinen aktiivisuus on tärkeä osa ikääntyvän ihmisen elämässä. Harjoittelun on todettu vaikuttavan reaktionopeuteen parantavasti. Tutkimuksen tarkoituksena oli tutkia …

NURE: An ERC project to study nuclear reactions for neutrinoless double beta decay

2017

Neutrinoless double beta decay (0{\nu}\b{eta}\b{eta}) is considered the best potential resource to determine the absolute neutrino mass scale. Moreover, if observed, it will signal that the total lepton number is not conserved and neutrinos are their own anti-particles. Presently, this physics case is one of the most important research beyond Standard Model and might guide the way towards a Grand Unified Theory of fundamental interactions. Since the \b{eta}\b{eta} decay process involves nuclei, its analysis necessarily implies nuclear structure issues. The 0{\nu}\b{eta}\b{eta} decay rate can be expressed as a product of independent factors: the phase-space factors, the nuclear matrix elemen…

First-forbidden transitions in reactor antineutrino spectra

2019

© 2019 American Physical Society. We study the dominant forbidden transitions in the antineutrino spectra of the fission actinides from 4 MeV onward using the nuclear shell model. Through explicit calculation of the shape factor, we show the expected changes in cumulative electron and antineutrino spectra. Relative to the allowed approximation this results in a minor decrease of electron spectra above 4 MeV, whereas an increase of several percent is observed in antineutrino spectra. We show that forbidden transitions dominate the spectral flux for most of the experimentally accessible range. Based on the shell model calculations we attempt a parametrization of forbidden transitions and prop…

Conformationally Locked Pyramidality Explains the Diastereoselectivity in the Methylation of trans-Fused Butyrolactones

2020

A stereoselectivity model inspired by the total synthesis of stemona alkaloids is developed to explain why enolate-derived 3,4-fused butyrolactones are methylated with a preference for syn alkylation. The model shows how conformational locking present in nonplanar enolate structures favors syn over anti methylation, due to less significant structural distortions in the syn pathway. The developed model was also successfully used to rationalize selectivities of previously documented methylation reactions. peerReviewed