1,070 research outputs found
Which aspects of ADHD are associated with tobacco use in early adolescence?
Several studies have found a relationship between attention-deficit hyperactivity disorder (ADHD) and substance use, primarily in the context of co-occuring conduct disorder (CD). However, very few have examined the associations between the individual dimensions of ADHD (hyperactivity-impulsivity and inattention) and substance use, even though these dimensions reflect distinct symptom groupings, both by clinical definition (DSM-IV, American Psychiatric Association, 1994) and through empirical demonstration (Lahey et al., 1988; McBurnett et al., 1999). This longitudinal study examines the relationship between dimensions of ADHD (as described by DSM) and substance use, accounting for other psychopathology and factors potentially related to substance use. Participants were 177 clinic-referred boys (initially between ages 7 and 12) followed up over nine annual phases until all participants had reached age 15. Annual assessment included structured clinical interviews with parent and child and self-report questionnaires of substance use, as well as questionnaires related to family factors and parenting behaviors. Seventy-eight per cent of participants reported use of tobacco, alcohol, marijuana, or other illicit drugs during adolescence, with 51% reporting any tobacco use. The inclusion of CD rendered all bivariate relationships with the full diagnosis of ADHD nonsignificant. However, adolescent inattention, considered independently, was associated with a 2.2 times greater risk for concurrent tobacco use, even after controlling for CD. Even when other factors, selected based on their associations with tobacco use in adolescence, were included in a regression model (concurrent adolescent CD odds ratio [OR] = 6.08), duration of tobacco use by age 12 (OR = 5.11), poor parental communication in childhood (OR = 2.9), African-American ethnicity (inversely predictive; OR = 0.15), inattention (OR = 2.3) remained significantly associated with tobacco use in early adolescence. These findings highlight the importance of considering the risks for comorbid substance use separately by individual dimensions of ADHD
Observable Effects of Scalar Fields and Varying Constants
We show by using the method of matched asymptotic expansions that a
sufficient condition can be derived which determines when a local experiment
will detect the cosmological variation of a scalar field which is driving the
spacetime variation of a supposed constant of Nature. We extend our earlier
analyses of this problem by including the possibility that the local region is
undergoing collapse inside a virialised structure, like a galaxy or galaxy
cluster. We show by direct calculation that the sufficient condition is met to
high precision in our own local region and we can therefore legitimately use
local observations to place constraints upon the variation of "constants" of
Nature on cosmological scales.Comment: Invited Festscrift Articl
Ariel - Volume 6 Number 3
Editors
Mark Dembert
J.D. Kanofsky
Frank Chervenak
John Lammie
Curt Cummings
Staff
Ken Jaffe
Bob Sklaroff
Halley Faust
Jim Burke
Nancy Redfern
Hans Weltin
Photographer
Larry Glazerman
Overseas Editor
Mike Sinason
Humorist
Jim McCan
Ariel - Volume 6 Number 2
Editors
Mark Dembert
J.D. Kanofsky
Frank Chervenak
John Lammie
Curt Cummings
Entertainment
Robert Breckenridge
Joe Conti
Gary Kaskey
Photographer
Larry Glazerman
Overseas Editor
Mike Sinason
Humorist
Jim McCann
Staff
Ken Jaffe
Bob Skarloff
Halley Faust
Jim Burk
Ariel - Volume 6 Number 4
Editors
Mark Dembert
J.D. Kanofsky
Frank Chervenak
John Lammie
Curt Cummings
Entertainment
Robert Breckenridge
Joe Conti
Gary Kaskey
Photographer
Larry Glazerman
Overseas Editor
Mike Sinason
Humorist
Jim McCann
Staff
Ken Jaffe
Bob Sklaroff
Halley Faust
Jim Burk
Ariel - Volume 6 Number 4 (Alternate Version)
Editors
Mark Dembert
J.D. Kanofsky
Frank Chervenak
John Lammie
Curt Cummings
Entertainment
Robert Breckenridge
Joe Conti
Gary Kaskey
Photographer
Larry Glazerman
Overseas Editor
Mike Sinason
Humorist
Jim McCann
Staff
Kenn Jaffe
Bob Sklaroff
Halley Faust
Jim Burke
Jay Amsterdam
Morton A. Klein
Nancy Redfer
Partial Dynamical SU(3) Symmetry and the Nature of the Lowest K=0 Collective Excitation in Deformed Nuclei
We discuss the implications of partial dynamical SU(3) symmetry (PDS) for the
structure of the lowest K=0^{+} (K=0_2) collective excitation in deformed
nuclei. We consider an interacting boson model Hamiltonian whose ground and
gamma bands have good SU(3) symmetry while the K=0_2 band is mixed. It is shown
that the double-phonon components in the K=0_2 wave function arise from SU(3)
admixtures which, in turn, can be determined from absolute E2 rates connecting
the K=0_2 and ground bands. An explicit expression is derived for these
admixtures in terms of the ratio of K=0_2 and gamma bandhead energies. The
SU(3) PDS predictions are compared with existing data and with broken-SU(3)
calculations for ^{168}Er.Comment: 12 pages, 2 figure
Ferromagnetic phase transition and Bose-Einstein condensation in spinor Bose gases
Phase transitions in spinor Bose gases with ferromagnetic (FM) couplings are
studied via mean-field theory. We show that an infinitesimal value of the
coupling can induce a FM phase transition at a finite temperature always above
the critical temperature of Bose-Einstein condensation. This contrasts sharply
with the case of Fermi gases, in which the Stoner coupling can not lead
to a FM phase transition unless it is larger than a threshold value . The
FM coupling also increases the critical temperatures of both the ferromagnetic
transition and the Bose-Einstein condensation.Comment: 4 pages, 4 figure
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