943 research outputs found

    Letter to the Editor: Robustness is the kind of coherence that matters: a comment on Kendler (2015)

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    Don't blame the model:Reconsidering the network approach to psychopathology

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    The network approach to psychopathology is becoming increasingly popular. The motivation for this approach is to provide a replacement for the problematic common cause perspective and the associated latent variable model, where symptoms are taken to be mere effects of a common cause (the disorder itself). The idea is that the latent variable model is plausible for medical diseases, but unrealistic for mental disorders, which should rather be conceptualized as networks of directly interacting symptoms. We argue that this rationale for the network approach is misguided. Latent variable (or common cause) models are not inherently problematic, and there is not even a clear boundary where network models end and latent variable (or common cause) models begin. We also argue that focusing on this contrast has led to an unrealistic view of testing and finding support for the network approach, as well as an oversimplified picture of the relationship between medical diseases and mental disorders. As an alternative, we point out more essential contrasts, such as the contrast between dynamic and static modeling approaches that can provide a better framework for conceptualizing mental disorders. Finally, we discuss several topics and open problems that need to be addressed in order to make the network approach more concrete and to move the field of psychological network research forward. (PsycINFO Database Recor

    Q-Value for the Fermi Beta-Decay of 46V

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    By comparing the Q-values for the 46Ti(3He,t)46V and 47Ti(3He,t)47}V reactions to the isobaric analog states the Q-value for the superallowed Fermi-decay of 46V has been determined as Q_{EC}(46V)=(7052.11+/-0.27) keV. The result is compatible with the values from two recent direct mass measurements but is at variance with the previously most precise reaction Q-value. As additional input quantity we have determined the neutron separation energy S_n(47Ti)=(8880.51+/-0.25) keV

    Laser Spectroscopy of Niobium Fission Fragments: First Use of Optical Pumping in an Ion Beam Cooler Buncher

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    A new method of optical pumping in an ion beam cooler buncher has been developed to selectively enhance ionic metastable state populations. The technique permits the study of elements previously inaccessible to laser spectroscopy and has been applied here to the study of Nb. Model independent mean-square charge radii and nuclear moments have been studied for 90,90m,91,91m,92,93,99,101,103^{90,90 m,91,91 m,92,93,99,101,103}Nb to cover the region of the N=50 shell closure and N≈60 sudden onset of deformation. The increase in mean-square charge radius is observed to be less than that for Y, with a substantial degree of ÎČ softness observed before and after N=60

    Palaeoecological evidence of changes in vegetation and climate during the Holocene in the pre-Polar Urals, northeast European Russia

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    This study investigated Holocene tree-line history and climatic change in the pre-Polar Urals, northeast European Russia. A sediment core from Mezhgornoe Lake situated at the present-day alpine tree-line was studied for pollen, plant macrofossils, Cladocera and diatoms. A peat section from Vangyr Mire in the nearby mixed mountain taiga zone was analysed for pollen. The results suggest that the study area experienced a climatic optimum in the early Holocene and that summer temperatures were at least 2°C warmer than today. Tree birch immigrated to the Mezhgornoe Lake area at the onset of the Holocene. Mixed spruce forests followed at ca. 9500-9000 14C yr BP. Climate was moist and the water level of Mezhgornoe Lake rose rapidly. The hypsithermal phase lasted until ca. 5500-4500 14C yr BP, after which the mixed forest withdrew from the Mezhgornoe catchment as a result of the climate cooling. The gradual altitudinal downward shift of vegetation zones resulted in the present situation, with larch forming the tree-line

    Left prefrontal repetitive transcranial magnetic stimulation in schizophrenia

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    In a double-blind, controlled study, we examined the therapeutic effects of high-frequency left prefrontal repetitive transcranial magnetic stimulation (rTMS) on schizophrenia symptoms. A total of 22 chronic hospitalized schizophrenia patients were randomly assigned to 2 weeks (10 sessions) of real or sham rTMS. rTMS was given with the following parameters: 20 trains of 5-second 10-Hz stimulation at 100 percent motor threshold, 30 seconds apart. Effects on positive and negative symptoms, self-reported symptoms, rough neuropsychological functioning, and hormones were assessed. Although there was a significant improvement in both groups in most of the symptom measures, no real differences were found between the groups. A decrease of more than 20 percent in the total PANSS score was found in 7 control subjects but only 1 subject from the real rTMS group. There was no change in hormone levels or neuropsychological functioning, measured by the MMSE, in either group. Left prefrontal rTMS (with the used parameters) seems to produce a significant nonspecific effect of the treatment procedure but no therapeutic effect in the most chronic and severely ill schizophrenia patients.Peer reviewe

    Q_EC values of the Superallowed beta-Emitters 10-C, 34-Ar, 38-Ca and 46-V

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    The Q_EC values of the superallowed beta+ emitters 10-C, 34-Ar, 38-Ca and 46-V have been measured with a Penning-trap mass spectrometer to be 3648.12(8), 6061.83(8), 6612.12(7) and 7052.44(10) keV, respectively. All four values are substantially improved in precision over previous results.Comment: 9 pages, 7 figures, 5 table

    Precision mass measurements on neutron-rich rare-earth isotopes at JYFLTRAP - reduced neutron pairing and implications for the rr-process calculations

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    The rare-earth peak in the rr-process abundance pattern depends sensitively on both the astrophysical conditions and subtle changes in nuclear structure in the region. This work takes an important step elucidating the nuclear structure and reducing the uncertainties in rr-process calculations via precise atomic mass measurements at the JYFLTRAP double Penning trap. 158^{158}Nd, 160^{160}Pm, 162^{162}Sm, and 164−166^{164-166}Gd have been measured for the first time and the precisions for 156^{156}Nd, 158^{158}Pm, 162,163^{162,163}Eu, 163^{163}Gd, and 164^{164}Tb have been improved considerably. Nuclear structure has been probed via two-neutron separation energies S2nS_{2n} and neutron pairing energy metrics DnD_n. The data do not support the existence of a subshell closure at N=100N=100. Neutron pairing has been found to be weaker than predicted by theoretical mass models. The impact on the calculated rr-process abundances has been studied. Substantial changes resulting in a smoother abundance distribution and a better agreement with the solar rr-process abundances are observed.Comment: 8 pages, 4 figures, accepted for publication in Physical Review Letter
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