Potentiometric analysis of sea water II. Determination of titration alkalinity

Sea water is alkaline mainly due to the presence of appreciable quantities of carbonate, bicarbonate and borate ions. These react with the H+ from the ionization of water leaving an excess of OH\u27 present…

Potentiometric analysis of sea water I. Determination of chlorinity

In general the determination of chlorinity of sea water is made by the classical Mohr method except when greater accuracy is desired in which case the more accurate but longer Volhard method is used. When the results are utilized for hydrodynamical considerations the Mohr method is normally used because of its speed in the titration of the numerous samples; but to attain the accuracy required in this exacting work, extreme care is demanded with the shaking during titration and in the proper selection of end point

Implementation of B-Trees Using Dynamic Address Computation

The B-tree is probably the most popular method in use today for indexes and inverted files in database management systems. The traditional implementation for a B-tree uses many pointers (more than one per key), and which can directly affect the performance of the B-tree. A general method of file organization and access (called Dynamic Address Computation) has been described by Cook that can be used to implement B-trees using no pointers. A minimal amount of storage (in addition to the keys) is required. This paper gives a detailed description of Direct Address Computation and the resulting system is analyzed, leading to the conclusion that, while the approach results in a simple implementation of B-trees, more work is required to achieve performance for large B-trees

Lysophosphatidic Acid Acyltransferase β (LPAATβ) Promotes the Tumor Growth of Human Osteosarcoma

Osteosarcoma is the most common primary malignancy of bone with poorly characterized molecular pathways important in its pathogenesis. Increasing evidence indicates that elevated lipid biosynthesis is a characteristic feature of cancer. We sought to investigate the role of lysophosphatidic acid acyltransferase β (LPAATβ, aka, AGPAT2) in regulating the proliferation and growth of human osteosarcoma cells. LPAATβ can generate phosphatidic acid, which plays a key role in lipid biosynthesis as well as in cell proliferation and survival. Although elevated expression of LPAATβ has been reported in several types of human tumors, the role of LPAATβ in osteosarcoma progression has yet to be elucidated.Endogenous expression of LPAATβ in osteosarcoma cell lines is analyzed by using semi-quantitative PCR and immunohistochemical staining. Adenovirus-mediated overexpression of LPAATβ and silencing LPAATβ expression is employed to determine the effect of LPAATβ on osteosarcoma cell proliferation and migration in vitro and osteosarcoma tumor growth in vivo. We have found that expression of LPAATβ is readily detected in 8 of the 10 analyzed human osteosarcoma lines. Exogenous expression of LPAATβ promotes osteosarcoma cell proliferation and migration, while silencing LPAATβ expression inhibits these cellular characteristics. We further demonstrate that exogenous expression of LPAATβ effectively promotes tumor growth, while knockdown of LPAATβ expression inhibits tumor growth in an orthotopic xenograft model of human osteosarcoma.Our results strongly suggest that LPAATβ expression may be associated with the aggressive phenotypes of human osteosarcoma and that LPAATβ may play an important role in regulating osteosarcoma cell proliferation and tumor growth. Thus, targeting LPAATβ may be exploited as a novel therapeutic strategy for the clinical management of osteosarcoma. This is especially attractive given the availability of selective pharmacological inhibitors

The Art of Noticing : An Essay on Contemporary Ecological Writing

A number of thinkers are becoming increasingly persuaded that our anthropocentric view of nature is inadequate, that we need a "new morality" with regard to the environment. In this essay, I argue that an alternative to anthropocentricism is available to us now-and has been since at least 1836. I look at three "checkpoints" in the evolution of environmental theory as proof of this: 1) the publication of Emerson's book Nature, 2) Aldo Leopold's A Sand County Almanac, and 3) the contemporary writing of Gretel Ehrlich, Gary Snyder, Wendell Berry, Mary Oliver, and A. R. Ammons. In short, I show that all these writers describe an aesthetic basis with which we may view nature that leads to a system of ethical values. What they advocate is a "moral framework" which I call noticing. My primary thesis is that we don't need a "new morality": we need only turn to the existing one these writers describe-and acknowledge it

Bacterial biodiversity in deep-sea sediments from two regions of contrasting surface water productivity near the Crozet Islands, Southern Ocean

The relationship between surface-derived particulate organic matter (POM) and deep-sea sediment bacterial abundance, community structure and composition was investigated in two different sediment layers from two zones of contrasting surface water productivity in the southern Indian Ocean. Bacterial sediment communities from high chlorophyll (HC) and low chlorophyll (LC) sites were characterized and compared using direct counts, clone library construction, denaturing gradient gel electrophoresis (DGGE) and fluorescence in situ hybridization (FISH). Of the 1566 bacterial clones generated from the sediment communities, 1010 matched published 16 S rDNA sequences at ?97% identity. A comparison of surface sediment clone libraries showed that at least one third of all identified operational taxonomic units (OTUs) were common to both HC and LC sites. DGGE community profiles were consistent (82% similar) and evenness of the major phylogenetic groups was 96% similar between surface sediment communities, where gamma- and alpha-Proteobacteria were dominant. Sediment communities shared similarly high biodiversity, while species richness was marginally higher at the LC site. Intra-site shifts in bacterial abundance and composition were observed with increasing sediment depth. Despite the differences in organic matter input between sites, the consistency observed between HC and LC sediment communities pointed to 1) the extent of remineralisation by mega and meio-fauna was a factor affecting the quantity and quality of POM available to sediment bacteria, 2) sampling during the early ‘nutrient assimilation phase’ of the bacterial response to freshly deposited POM or 3) the action of bacteria in the water column could affect the quantity and quality of POM available to sediment bacteria. Although factors other than these may explain the observed similarities, this first comparison of deep-sea sediment communities in relation to surface-derived productivity may be useful in further elucidating the role of sediment bacteria in carbon remineralisation in the deep-sea environment

Strengthening Historic Covered Bridges To Carry Modern Traffic

DTFH61-00-C-00081In this research project, the Constructed Facilities Center (CFC) and the Institute for the History of Technology and Industrial Archaeology (IHTIA) of West Virginia University (WVU) teamed up to develop means and methods to strengthen wooden superstructure components of historic covered bridges, using glass-fiber reinforced polymer (GFRP) composite materials. The strengthening methodologies developed in this project were designed to conform to the Secretary of the Interior\u2019s Standard for Historic Preservation. Specifically, tension and bending tests were conducted to establish the bond strength of GFRP rebars embedded in wood, and to establish the bending strength and stiffness of large-scale floor beams reinforced with GFRP pultruded plates and with GFRP rebars. In addition, methods were developed to enhance the shear capacity of large-scale floor beams reinforced with GFRP pultruded plates bonded on edge in narrow, prerouted vertical slots. The GFRP rebars were developed to be used specifically as axial reinforcement for truss members, while the GFRP were developed to increase the bending and shear capacity of floor beams. The test results showed bonded-in GFRP rebars performed very well in terms of pullout force and bond strength, and the strength and stiffness of GFRP-reinforced floor beams improved significantly. Although the shear strength was also expected to improve considerably with the addition of the GFRP plates placed on edge (resulting in a flitched beam), the shear capacity decreased slightly. The flitched beams tested were severely checked, which degraded their shear strength as compared to the solid control specimen. Further testing will continue in a succeeding study. Additionally, during this research, several methods of concealing the reinforcement were investigated. One successful method took advantage of routing a member on the bottom face and bonding a GFRP plate with an integrated veil to match the wood grain and color of the original aged wood