Empirical studies and theory have identified many early predictors of children's academic achievement and externalizing problems. Moreover, research shows that children's early cognitive abilities and behavioral problems are strong predictors of later academic achievement and externalizing problems. The current dissertation studies extend previous work and unpack how early predictors relate...
Executive functions (including attentional shifting/flexibility, working memory, and inhibitory control) are strong predictors of children's early school success (Blair & Razza, 2007; Espy et al., 2004). The current study explored questions related to measurement of executive functions in preschool-aged children. Convergent and predictive validity were assessed for two traditional executive...
K-Ar and ⁴⁰Ar-³⁹Ar geochronologic
data reveal the Paleocene to Eocene eruptive
history of volcanic centers which produced the
basaltic basement rocks of the Coast Range of
Oregon and Washington. Volcanism was short
lived at each center and migrated with time from
the northern and southern ends toward the
center, near...
Radiometric ages (K-Ar and ⁴⁰Ar-
³⁹Ar methods) have been determined on dredged
volcanic rocks from seven of the New England
Seamounts, a prominent northwest-southeast trending
volcanic lineament in the northwestern
Atlantic Ocean. The ⁴⁰Ar-³⁹Ar total fusion and
incremental heating ages show an increase in
seamount construction age from southeast to...
A succession of basaltic lavas, volcaniclastic sediments, and lignite beds in the Holmatindur region of eastern Iceland provides the means for tying magnetic reversal stratigraphy and a record of major North Atlantic cooling to a precise radiometric timescale. A prominent part of the section is the Holmatindur classic bed, which...
We report the behavior of the earth's magnetic field for a transition recorded in lavas at the volcanic island of
Huahine in French Polynesia, south-central Pacific Ocean. Detailed intermediate fields are observed that record an
apparent N-N excursion. The available K-Ar ages indicate that most volcanic rocks of the southern...
Results of ⁴⁰Ar–³⁹Ar Ar dating constrain the age of the submerged volcanic succession, part of the seaward-dip ping reflector sequence of the Southeast Greenland volcanic rifted margin, recovered during Leg 163. At the 3°Ne 6 drilling transect, the fully normally magnetized volcanic units at Holes 989B (Unit 1) and 990A...
Crystallization ages of volcanic rocks, dredged or drilled from the Walvis Ridge (ten sites) and the Rio
Grande Rise (one site), have been determined by the ⁴⁰Ar/³⁹Ar incremental heating technique. The
fundamentally age-progressive distribution of these basement ages suggests a common hot spot source for
volcanism on the island of...
New K-Ar age determinations on
basalts, basaltic andesites, and ash flow
tuffs from the central Western Cascades in
Oregon range in age from 32 to 3 Ma. The
ages decrease from west to east and with
increasing elevation. Volcanism has been
continuous throughout the evolution of the
Western Cascades, with...
A volcanic sequence almost 700 meters thick has been sampled in the Punaruu valley on the island of
Tahiti, southern central Pacific Ocean. Detailed paleomagnetic results have been obtained from 123 sites. Three
reversals are recorded in this sequence. Age determinations (K-Ar) indicate that the youngest reversal corresponds
to the...
