It is critical to study factors that are important for origin and maintenance of biological
diversity. A comparative approach involving a large number of populations is
particularly useful.We use this approach to study the relationship between ecological
factors and phenotypic diversity in Icelandic Arctic charr (Salvelinus alpinus).
Numerous populations of...
I studied the occurrence of two sympatric morphs of arctic charr, Salvelinus
alpinus (L.) in Vatnshlidarvatn, a small shallow lake in NW Iceland. The arctic charr
were subjectively distinguished by colour and appearance as brown morph or silver
morph, and measured for morphological and life history characters. The study
revealed...
We report paleointensity results of the Earth's
magnetic field from n Late Pleistocene lava flow
(Louchadiere, Central France), which recorded an intermediate
geomagnetic field direction (5 sites, mean declination=
114.1°, inclination=58.2°, k=130, α95=6.7°). New K-Ar
age determinations confirm that this flow is contemporaneous
with the Laschamp and Olby flows, and...
Understanding the origin and nature of intra specific biodiversity enables us to better conserve and manage animal populations. Biological diversity is seen at different scales and for different traits such as behavior, morphology, physiology, and life history. Behavior is especially important since behavioral changes are believed to precede changes in...
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...
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...
Obesity and food insecurity rates are higher among rural compared to non-rural populations. Little is known, however, about how family-home environments influence childhood obesity-related behaviors, particularly in rural settings. This study examined associations between the family-home nutrition (FN) environment, food insecurity, and dietary intake (fruits, vegetables, whole grains, dairy, protein...
The island of Tahiti, the largest in French Polynesia, comprises two major volcanoes aligned NW-SE, parallel with the general trend of the Society Islands hotspot track. Rocks form this volcanic system are basalts transitional to tholeiites, alkali basalts, basanites, picrites, and evolved lavas. Through K-Ar radiometric dating we have established...
At low latitudes, cirrus are ubiquitous and can be in
excess of 100°C colder than the surface, limiting the
amount of sunlight absorbed by the earth’s atmosphere and
surface, and reducing its loss of heat. Here we present
aircraft measurements within cirrus over southern Florida
indicating that ice crystals have...