Stratigraphy and chronology of Holocene marine sedment core from the California continental borderland and their paleoceanographic/paleoclimatic significance [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Paleomagnetic secular variation (PSV) records have been recovered from three marine sediment cores from Santa Catalina basin, California continental borderland, in order to more accurately date these late Quaternary sediments. ... The sedimentation rates derived from the time/depth curves suggest a constant rate of 20-25 cm/ky for the last 6700 years throughout Santa Catalina basin, and more variable rates (but constant within each core) of 13-86 cm/ky prior to 6700 ybp. The sedimentation rates prior to 6700 ybp are lowest in the southcentral portion of the basin and systematically increase toward the north end of the basin. These results suggest that 6700±300 ybp marks a major change in paleoceanographic processes within Santa Catalina basin.

Seasonal resolution of laminated sediments in Santa Barbara Basin: its significance in paleoclimatic studies

Sediments in Santa Barbara Basin contain microfossil and sedimentological information that allows reconstruction of major features of the California Current such as water temperature, strength of upwelling, and productivity. ... Until now, investigations of Santa Barbara Basin sediments have utilized analytical techniques that could not resolve seasonal laminae, permitting annual resolution of variations in sediment composition and structure only. ... Based on a successful technique for preparation of epoxy-embedded and highly polished thin-sections that permit economical optical and electron microscope evaluation of laminated sequences, it is our long-term goal to reconstruct, with unprecedented detail, the history of sedimentation processes in the Santa Barbara Basin by developing ultra-high-resolution time series of biotic and detrital proxies.

Aquacrops of Darbhanga District in north Bihar and their commercial significance

Darbhanga district in North Bihar is characterised by thick alluvial soil, moderately good rainfall, high humidity, ample sunshine and numerous water resources in the form of perennial rivers, tributaries, streams, lakes, ponds, pools and puddles. The aquacrops of this district include several species of commercially important fishes, aquatic cash crops such as makhana (Euryale ferox), singhara (Trapa spp.), lotus, lilly, Khubi etc. and molluscs. This paper highlights the commercial significance of these aquacrops and offers suggestions for their sustained development.

Hydrography of the Bay of Bengal during south west monsoon and its significance on oil sardine fishery

Hydrographic data collected from east coast of India during 1994 monsoon period revealed that these waters are highly characterized by upwelling especially in the coastal waters with more intensity in the southern part of the region. However, the near surface salinity stratification consequent to high fresh water inflow into the bay was absent in the present study. Oil sardines are directly influenced by hydrographic parameters such as salinity and temperature and stratification of these parameters are the major reasons for non-availability/migration of oil sardine from this region in the earlier years. Considering the recent topographical change in the east coast coupled with hydrological stability an attempt has been made in this paper to give reasonable justification to the reported bumper catches of oil sardines from 1994 on wards in the east coast of India.

Functional significance of stiffness in adaptation of multijoint arm movements to stable and unstable dynamics.

This study compared the mechanisms of adaptation to stable and unstable dynamics from the perspective of changes in joint mechanics. Subjects were instructed to make point to point movements in force fields generated by a robotic manipulandum which interacted with the arm in either a stable or an unstable manner. After subjects adjusted to the initial disturbing effects of the force fields they were able to produce normal straight movements to the target. In the case of the stable interaction, subjects modified the joint torques in order to appropriately compensate for the force field. No change in joint torque or endpoint force was required or observed in the case of the unstable interaction. After adaptation, the endpoint stiffness of the arm was measured by applying displacements to the hand in eight different directions midway through the movements. This was compared to the stiffness measured similarly during movements in a null force field. After adaptation, the endpoint stiffness under both the stable and unstable dynamics was modified relative to the null field. Adaptation to unstable dynamics was achieved by selective modification of endpoint stiffness in the direction of the instability. To investigate whether the change in endpoint stiffness could be accounted for by change in joint torque or endpoint force, we estimated the change in stiffness on each trial based on the change in joint torque relative to the null field. For stable dynamics the change in endpoint stiffness was accurately predicted. However, for unstable dynamics the change in endpoint stiffness could not be reproduced. In fact, the predicted endpoint stiffness was similar to that in the null force field. Thus, the change in endpoint stiffness seen after adaptation to stable dynamics was directly related to changes in net joint torque necessary to compensate for the dynamics in contrast to adaptation to unstable dynamics, where a selective change in endpoint stiffness occurred without any modification of net joint torque.