Documenting 6,000 Years of Indigenous Fisheries and Settlement as Seen through Vibracore Sampling on the Central Coast of British Columbia, Canada

This article highlights the utility of vibracore technology to sample deep shell midden deposits on the Central Pacific Coast of British Columbia, Canada. Analysis of six core samples and 21 radiocarbon dates revealed that the archaeological deposits extended to a depth of 544 cm below surface and that occupation began approximately 6,000 years ago, continuing into the sixteenth century AD. Zooarchaeological identification of fine screened (2 mm) sediments shows that fish constitute 99.8% of identified vertebrate fauna, with a focus on herring (Clupea pallasii), salmon (Oncorhynchus sp.), rockfish (Sebastes sp.), and greenling (Hexagrammos sp.), followed by a variety of other fish taxa utilized throughout the occupation of this site. Despite a much smaller examined volume relative to conventional excavation, vibracoring was effective in recovering deep, stratigraphically intact, and adequate samples of zooarchaeological fisheries data as well as a considerable number of stone, bone, and shell artifacts (an estimated 550 artifacts per cubic meter of cultural sediments). These results show a persistent and sustainable ancient fishery through six millennia until the contact period. The field and laboratory methods described are especially conducive to sampling large and deep shell midden deposits repetitively.

Modeling convection and zonal winds in giant planets

Three basic modeling approaches have been used to numerically simulate fluid turbulence and the banded zonal winds in the interiors and atmospheres of giant planets: shallow-water models, deep-shell Boussinesq models and deep-shell anelastic models. We review these models and discuss the approximations and assumptions upon which they are based. All three can produce banded zonal wind patterns at the surface. However, shallow-water models produce a retrograde (i.e., westward) zonal jet in the equatorial region, whereas strong prograde (i.e., eastward) equatorial jets exist on Jupiter and Saturn. Deep-shell Boussinesq models maintain prograde equatorial jets by the classic method of vortex stretching of convective columnar flows; however, they neglect the effects of the large density stratification in these giant planets. Deep-shell anelastic models account for density stratification and maintain prograde equatorial jets by generating vorticity as rising fluid expands and sinking fluid contracts, without the constraint of long thin convective columns.

Differences in Neuronal Firing Rates in Pallidal and Cerebellar Receiving Areas of Thalamus in Patients With Parkinson's Disease, Essential Tremor, and Pain

The motor symptoms of Parkinson's disease (PD) are thought to result from increased inhibitory outflow from the basal ganglia to the pallidal receiving areas of thalamus (ventral oral anterior and posterior—Voa,Vop). To test this hypothesis, we examined the firing rates of neurons in pallidal and cerebellar receiving areas of thalamus in five PD patients and compared them to those of neurons in comparable regions of motor thalamus in two other patient groups where hyperactivity of GPi is not believed to occur [essential tremor (ET), pain]. Neuronal recordings were made during microelectrode-guided functional stereotactic neurosurgery. The mean spontaneous firing rate (MSFR) of neurons classified as voluntary neurons and presumed to be in pallidal receiving areas of thalamus in PD patients [7.4 ± 1.0 (SE) Hz] was significantly lower ( P < 0.01) than in the ET (18.1 ± 3.0 Hz) and pain (19.0 ± 1.9Hz) groups. In contrast, the MSFR of neurons classified as kinesthetic and presumed to be primarily in the cerebellar receiving area of thalamus (ventral intermediate—Vim), although some are probably in the deep shell region of the ventrocaudal nucleus (VPLa), was significantly greater in ET patients (25.8 ± 3.5 Hz) than in the PD (14.3 ± 1.6 Hz; P < 0.01) and pain (16.1 ± 1.5 Hz; P < 0.05) groups. Similar findings were obtained when the neurons were grouped according to their estimated locations in Voa/Vop and Vim of motor thalamus. These data provide support for the prediction of the classical pathophysiological model of PD and moreover suggest that pathophysiology in the cerebello-thalamo-cortical pathway may be a possible cause of tremor in ET patients.

Further Studies of General Shells by Hybrid Strain Based Triangular Elements

This paper presents a further study of various lower-order flat triangular shell elements that were based on the Hellinger-Reissner hybrid strain formulation and were developed previously by the authors. The present investigation is to examine the effects of including membrane-bending coupling feature in the shell element formulation on the performance of the lower-order shell elements. Several features are considered. These are, for example, the membrane-bending coupling, tue linear distribution of the assumed strain field of the membrane strain, and the hybrid strain formulation with linear assumed membrane strains and membrane-bending coupling. A study on mesh topology is also included. This relatively detailed study leads one to the conclusion that the hybrid strain based flat triangular shell elements previously developed by the authors are attractive and promising for economical analysis of general shells. It is also found that the inclusion of features such as membrane-bending coupling is unnecessary. Numerical results presented here seem to strongly substantiate the theoretical developments that flat triangular shell elements do converge to the correct solution of deep shell theory. Finally it is observed that for deep shell problems appropriate mesh topology becomes the key to an accurate finite element solution.