976 resultados para Scale 1:6,000None


Relevância:

100.00% 100.00%

Publicador:

Resumo:

This study attempts to understand the significance of Uvigerina proboscidea in paleoceanographic reconstructions at the northern (tropical) Indian Ocean DSDP Site 214 from the Late Miocene through the Pleistocene. In this interval at this site, U. proboscidea is the most abundant species of the benthic assemblage and shows abrupt frequency changes (about 1-74%). Based on relative percentages of U. proboscidea calibrated with oxygen and carbon isotope record and the sediment accumulation rates, the modern distribution of the species in the Indian Ocean, and other evidence, the peaks of abundance of U. proboscidea are inferred to represent times of high-surface productivity, This productivity is related to intensified trade winds during strong southwest (SW) Indian monsoons, causing widespread upwelling along equatorial divergemce in the Indian Ocean. The sudden increase of U. proboscidea abundance at approximately 8.5-7.5 Ma reflects significant upwelling at the equatorial divergence. This event corresponds to the permanent build-up of West Antarctic ice sheets, and a major increase in SW Indian monsoons related upwelling in the northwestern Indian Ocean. The Chron-6 carbon shift at approximately 6.2 Ma is marked by another peak of abundance, reflecting widespread ocean fertility. The highest abundances of U. proboscidea and highest sediment accumulation rates occur between 5.8 and 5.1 Ma, which coincidies with the greatest development of Antarctic ice sheets and strong southwest monsoons. The higher percentages at 3.2-3.1 Ma, approximately 2.4 Ma, and 1.6 Ma all represent phases of high productivity at the equatorial divergence.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Secondary carbonate minerals were recovered within the basalts at both ODP Sites 768 and 770 in the Sulu and Celebes seas. Petrographic and X-ray diffraction analyses indicate that the carbonates are calcites. Other alteration products recognized in the thin sections are smectites, iron oxides, and gypsum. The 13C values of carbonates from both sites range from 1.6 per mil to 2.3 per mil, which are indicative of inorganic carbonate formation with no contributions from 13C-depleted sources such as oxidized organic carbon or methane. The oxygen isotopes at Site 770 range from 30.8 per mil to 31.6 per mil, which indicates a pervasive circulation of cold seawater (9° to 12°C) during alteration of the Celebes Sea basalts. In contrast, carbonates associated with Site 768 basalts have less positive d18O values (21.0 per mil to 27.3 per mil). A lighter 18O isotopic signature indicates the formation of secondary calcite at either higher temperatures or in a system closed to seawater. The rapidly deposited pyroclastic flows at Site 768 would have limited water access to the crust very soon after its formation, which leads us to speculate that the carbonates in the Sulu Sea basalts were formed by isotopically modified fluids resulting from basalt alteration in a closed system.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Volume contains nos. 1-6.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Vols. 1-6 and index first issued separately in 1940; v. 2-3 revised and reissued separately in 1941.

Relevância:

100.00% 100.00%

Publicador:

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Double leaves, oriental style, in case.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Yellow and black ink on linen. Location, type of plantings. At lower right: Number 6 in pencil. Signed. 61 cm. x 28 cm. Scale: 1"=10' [from photographic copy by Lance Burgharrdt]

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Ink on linen; location, type of plantings; at lower right, "Sheet-p-6" unsigned. 133 x 63 cm. Scale: 1"=20' [from photographic copy by Lance Burgharrdt]

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Ink on linen; location, type of plantings; signed. 87x76 cm. Scale: 1"=30' [from photographic copy by Lance Burgharrdt]

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Ink on linen; location, type, amounts of plantings; grape arbors, tennis courts; note: "del, F.E.H."; signed; 56 x 33 cm; Scale: 1" = 20' [from photographic copy by Lance Burgharrdt]

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Rationale and Objectives. The authors attempt to provide a set of objectives for medical student training in radiology for contemporary medical practice. Materials and Methods. A questionnaire containing a list of educational objectives was sent to 32 radiologists in charge of medical student training in radiology at accredited residency programs in Australia and New Zealand. The importance of including each preselected objective in the curriculum was measured by respondents' agreement or disagreement on a scale of 1-6. Opportunity also was given to respondents to suggest objectives other than those presented on the questionnaire. Results. Twenty of the 32 questionnaires were returned, and a set of educational objectives was established based on the responses. The objectives were ranked in importance according to the mean score assigned to each objective by the respondents. Conclusion. This new set of educational objectives for medical student radiology training reflects recent changes in radiologic and medical practice and points to potential future developments.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The most potent known naturally occurring Bowman-Birk inhibitor, sunflower trypsin inhibitor-1 (SFTI-1), is a bicyclic 14-amino acid peptide from sunflower seeds comprising one disulfide bond and a cyclic backbone. At present, little is known about the cyclization mechanism of SFTI-1. We show here that an acyclic permutant of SFTI-1 open at its scissile bond, SFTI-1[ 6,5], also functions as an inhibitor of trypsin and that it can be enzymatically backbone-cyclized by incubation with bovine beta-trypsin. The resulting ratio of cyclic SFTI-1 to SFTI1[6,5] is similar to9:1 regardless of whether trypsin is incubated with SFTI-1[ 6,5] or SFTI-1. Enzymatic resynthesis of the scissile bond to form cyclic SFTI-1 is a novel mechanism of cyclization of SFTI-1[ 6,5]. Such a reaction could potentially occur on a trypsin affinity column as used in the original isolation procedure of SFTI-1. We therefore extracted SFTI-1 from sunflower seeds without a trypsin purification step and confirmed that the backbone of SFTI-1 is indeed naturally cyclic. Structural studies on SFTI-1[ 6,5] revealed high heterogeneity, and multiple species of SFTI-1[ 6,5] were identified. The main species closely resembles the structure of cyclic SFTI-1 with the broken binding loop able to rotate between a cis/trans geometry of the I7-P8 bond with the cis conformer being similar to the canonical binding loop conformation. The non-reactive loop adopts a beta-hairpin structure as in cyclic wild-type SFTI-1. Another species exhibits an isoaspartate residue at position 14 and provides implications for possible in vivo cyclization mechanisms.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We have rated eye color on a 3-point scale (1=blue/grey, 2=hazel/green, 3=brown) in 502 twin families and carried out a 5-10 cM genome scan (400-757 markers). We analyzed eye color as a threshold trait and performed multipoint sib pair linkage analysis using variance components analysis in Mx. A lod of 19.2 was found at the marker D15S1002, less than 1 cM from OCA2, which has been previously implicated in eye color variation. We estimate that 74% of variance in eye color liability is due to this QTL and a further 18% due to polygenic effects. However, a large shoulder on this peak suggests that other loci affecting eye color may be telomeric of OCA2 and inflating the QTL estimate. No other peaks reached genome-wide significance, although lods >2 were seen on 5p and 14q and lods >1 were additionally seen on chromosomes 2, 3, 6, 7, 8, 9, 17 and 18. Most of these secondary peaks were reduced or eliminated when we repeated the scan as a two locus analysis with the 15q linkage included, although this does not necessarily exclude them as false positives. We also estimated the interaction between the 15q QTL and the other marker locus but there was only minor evidence for additive x additive epistasis. Elaborating the analysis to the full two-locus model including non-additive main effects and interactions did not strengthen the evidence for epistasis. We conclude that most variation in eye color in Europeans is due to polymorphism in OCA2 but that there may be modifiers at several other loci.