25 research outputs found
Modelling the nucleon wave function from soft and hard processes
Current light-cone wave functions for the nucleon are unsatisfactory since
they are in conflict with the data of the nucleon's Dirac form factor at large
momentum transfer. Therefore, we attempt a determination of a new wave function
respecting theoretical ideas on its parameterization and satisfying the
following constraints: It should provide a soft Feynman contribution to the
proton's form factor in agreement with data; it should be consistent with
current parameterizations of the valence quark distribution functions and
lastly it should provide an acceptable value for the \jp \to N \bar N decay
width. The latter process is calculated within the modified perturbative
approach to hard exclusive reactions. A simultaneous fit to the three sets of
data leads to a wave function whose -dependent part, the distribution
amplitude, shows the same type of asymmetry as those distribution amplitudes
constrained by QCD sum rules. The asymmetry is however much more moderate as in
those amplitudes. Our distribution amplitude resembles the asymptotic one in
shape but the position of the maximum is somewhat shifted.Comment: 32 pages RevTex + PS-file with 5 figures in uu-encoded, compressed
fil
Altered orbitofrontal sulcogyral patterns in gambling disorder: a multicenter study
Gambling disorder is a serious psychiatric condition characterized by decision-making and reward processing
impairments that are associated with dysfunctional brain activity in the orbitofrontal cortex (OFC). However, it remains
unclear whether OFC functional abnormalities in gambling disorder are accompanied by structural abnormalities. We
addressed this question by examining the organization of sulci and gyri in the OFC. This organization is in place very
early and stable across life, such that OFC sulcogyral patterns (classified into Types I, II, and III) can be regarded as
potential pre-morbid markers of pathological conditions. We gathered structural brain data from nine existing studies,
reaching a total of 165 individuals with gambling disorder and 159 healthy controls. Our results, supported by both
frequentist and Bayesian statistics, show that the distribution of OFC sulcogyral patterns is skewed in individuals with
gambling disorder, with an increased prevalence of Type II pattern compared with healthy controls. Examination of
gambling severity did not reveal any significant relationship between OFC sulcogyral patterns and disease severity.
Altogether, our results provide evidence for a skewed distribution of OFC sulcogyral patterns in gambling disorder and
suggest that pattern Type II might represent a pre-morbid structural brain marker of the disease. It will be important to
investigate more closely the functional implications of these structural abnormalities in future work.Y.L. was supported by the National Natural Science Foundation of China (Grant
No. 31600929) and the Fundamental Research Funds for the Central
Universities (010914380002). G.S. was supported by a Veni grant from the
Netherlands Organization for Scientific Research (Grant No. 016.155.218). J.J.
was supported by the Academy of Finland (Grant No. 295580), the Finnish
Medical Foundation, and the Finnish Foundation for Alcohol Studies. V.K. was
supported by the Academy of Finland (Grant No. 256836) and the Finnish
Foundation for Alcohol Studies. S.G. and H.R.S. were supported by the Danish
Council for Independent Research in Social Sciences through a grant to
Thomas Ramsøy (“Decision Neuroscience Project”; Grant No. 0601-01361B) and
by the Lundbeck Foundation through a Grant of Excellence (“ContAct”; Grant
No. R59 A5399). A.G. was supported by Deutsche Forschungsgemeinschaft
(DFG) HE2597/15–1, HE2597/15–2, and DFG Graduiertenkolleg 1589/2 “Sensory
Computation in Neural Systems”. N.R.-S. was supported by a research grant by
the Senatsverwaltung für Gesundheit und Soziales, Berlin, Germany (Grant No.
002–2008/I B 35). C.M.R.d.L. and J.C.P. were supported by a grant from the
Spanish Government (Ministerio de Economía y Competitividad, Secretaría de
Estado de Investigación, Desarrollo e Innovación; Convocatoria 2017 de
Proyectos I+D de Excelencia, Spain; co-funded by the Fondo Europeo de
Desarrollo Regional, FEDER, European Union; Grant No. PSI2017–85488-P). J.-C.
D. was supported by “LABEX ANR-11-LABEX-0042” of Université de Lyon within
the program Investissements d’Avenir (ANR-11-IDEX-007) operated by the
French National Research Agency and by a grant from the Fondation pour la
Recherche Médicale (Grant No. DPA20140629796)