We investigated decays of ^{51,52,53}K at the ISOLDE Decay Station at CERN in order to understand the mechanism of the β-delayed neutron-emission (βn) process. The experiment quantified neutron and γ-ray emission paths for each precursor. We used this information to test the hypothesis, first formulated by Bohr in 1939, that neutrons in the βn process originate from the structureless "compound nucleus.
View Article and Find Full Text PDFWe report the results of a β-decay study of fission products ^{86}Br, ^{89}Kr, ^{89}Rb, ^{90gs}Rb, ^{90m}Rb, ^{90}Kr, ^{92}Rb, ^{139}Xe, and ^{142}Cs performed with the Modular Total Absorption Spectrometer (MTAS) and on-line mass-separated ion beams. These radioactivities were assessed by the Nuclear Energy Agency as having high priority for decay heat analysis during a nuclear fuel cycle. We observe a substantial increase in β feeding to high excited states in all daughter isotopes in comparison to earlier data.
View Article and Find Full Text PDFThe β-delayed neutron emission of ^{83,84}Ga isotopes was studied using the neutron time-of-flight technique. The measured neutron energy spectra showed emission from states at excitation energies high above the neutron separation energy and previously not observed in the β decay of midmass nuclei. The large decay strength deduced from the observed intense neutron emission is a signature of Gamow-Teller transformation.
View Article and Find Full Text PDFWe report total absorption spectroscopy measurements of ^{92}Rb, ^{96gs}Y, and ^{142}Cs β decays, which are the most important contributors to the high energy ν[over ¯]_{e} spectral shape in nuclear reactors. These three β decays contribute 43% of the ν[over ¯]_{e} flux near 5.5 MeV emitted by nuclear reactors.
View Article and Find Full Text PDFPhys Rev Lett
September 2013
Beta decay of 86Ga was studied by means of β-neutron-γ spectroscopy. An isotopically pure ^{86}Ga beam was produced at the Holifield Radioactive Ion Beam Facility using a resonance ionization laser ion source and high-resolution electromagnetic separation. The decay of 86Ga revealed a half-life of 43(-15)(+21) ms and large β-delayed one-neutron and two-neutron branching ratios of P1n=60(10)% and P2n=20(10)%.
View Article and Find Full Text PDFThe β decays of neutron-rich nuclei near the doubly magic (78)Ni were studied at the Holifield Radioactive Ion Beam Facility using an electromagnetic isobar separator. The half-lives of (82)Zn (228±10 ms), (83)Zn (117±20 ms), and (85)Ga (93±7 ms) were determined for the first time. These half-lives were found to be very different from the predictions of the global model used in astrophysical simulations.
View Article and Find Full Text PDFAs part of a longitudinal nosologic study of major depressive disorder (MDD), dysthymic disorder (DD), and adjustment disorder with depressed mood (ADDM) in a school-age cohort, we examined the prevalence and clinical consequences of comorbid anxiety disorders. We also estimated the risk of a first anxiety disorder and examined its predictors. Of 104 cases, 41% had anxiety disorders in conjunction with their index depression, which was more likely with MDD and DD than with ADDM.
View Article and Find Full Text PDFAs part of a longitudinal nosologic study of major depressive disorder (MDD), dysthymic disorder, and adjustment disorder with depressed mood in 104 school-aged probands, the prevalence and consequences of comorbid conduct disorders (CD) were examined. During the index depressive episodes, 16% of the patients had comorbid CD; during the full study observation 23% had CD; and the estimated time-dependent risk of conduct disorder developing was 36% by age 19. For most cases, comorbid CD developed as a complication of the depression and persisted after the depression remitted.
View Article and Find Full Text PDFPsychologic adjustment, assessed by self-ratings of anxiety, self-esteem, and depression, and cognitive as well as behavioral coping strategies, elicited by interview, were monitored longitudinally among school-age children with recent-onset insulin-dependent diabetes mellitus (IDDM). Our article documents the findings over the 1st yr of illness. From the start, the children viewed themselves as self-confident and emotionally comfortable.
View Article and Find Full Text PDFAs part of a prospective, longitudinal study of school-aged children with newly diagnosed insulin-dependent diabetes mellitus (IDDM), we examined how the parents adjusted to the illness. The present article documents this process for the first year of IDDM. We found no support for earlier claims that most parents resort to blatantly neurotic or psychopathologic behavior to cope.
View Article and Find Full Text PDFSchool-aged children with newly diagnosed insulin-dependent diabetes mellitus (IDDM) were studied longitudinally in order to document how they adjusted to the medical illness and to assess salient background factors. The extent of life stress and the prevalence of psychiatric disorders that predated the IDDM were within normative ranges, and there was no characteristic preexisting "diabetic personality." The initial strain of living with IDDM elicited two general modes of coping.
View Article and Find Full Text PDFAs part of a longitudinal nosologic study of major depressive disorder, dysthymic disorder (DD), and adjustment disorder with depressed mood ( ADDM ) in a school-aged cohort, the predictive validity of each diagnosis was examined. Using all available data on the course of the disorders, the criterion was the first subsequent major depressive episode. Major depressive disorder and DD signaled a similarly high risk of a new bout of depressive illness.
View Article and Find Full Text PDFIn the context of a prospective, longitudinal, and controlled nosologic study, the characteristics and diagnostic validity of major depressive disorder, dysthymic disorder, and adjustment disorder with depressed mood were examined in a school-aged cohort. The entities were distinguishable on several dimensions such as age at onset and pattern of recovery. Time to recovery from onset was most favorable for the adjustment disorders (90% remission rate during nine months) and least so for the dysthymias (89% remission rate during six years).
View Article and Find Full Text PDFJ Abnorm Child Psychol
December 1979
Hyperactive and matched control boys at two age levels were compared on teacher ratings of peer interaction and three measures of social perspective-taking. The teachers' ratings of peer interaction discriminated between the hyperactive children and their controls. In addition, a significant interaction effect indicated that teachers rated the older hyperactive group as more deviant with peers than both their younger hyperactive counterparts and their age-matched controls.
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