Chemical composition of bottom sediments from the Discovery Deep, Red Sea rift zone

Hot brines in depressions of the central Red Sea contain thousands of times more iron, manganese and other metals than . After removal of salts, approximately half of sediments from these depressions consists of iron hydroxides and they are enriched in zinc, copper, lead and molybdenum. Hydrothermal deposits with the same complex of metals, located along the coast of the Red Sea, are correlated with faults and may be due to occurrences of Tertiary volcanism. Brines of similar composition are known in the Cheleken Peninsula. Certain geological and geochemical data indicate that such brines are of relatively deep origin.

Silicoflagellates of early Paleocene to early Miocene sediments of the subantarctic South Atlantic

Nearly complete Paleogene sedimentary sequences were recovered by Leg 114 to the subantarctic South Atlantic. Silicoflagellate assemblages from the Paleogene and immediately overlying lower Neogene from Sites 698 (Northeast Georgia Rise), 700 (East Georgia Basin), 702 (Islas Orcadas Rise), and 703 (Meteor Rise) were examined. The described assemblage from Hole 700B represents the most complete yet described from the Paleocene, encompassing planktonic foraminifer Zones Plb (upper part) through P4 and Subchrons C25N to C23N. All lower Eocene sediments are barren as a result of diagenesis, except for a single sample from Hole 698A. Middle Eocene silicoflagellates described from Hole 702B range in age from early middle Eocene (P10) to late Eocene (PI5), with correlations to Subchrons C21N to C18N. Hole 703A contains late Eocene through early Miocene assemblages, with paleomagnetic control from Subchrons C16R to C6AAN. Leg 114 biosiliceous sequences contain exceptionally diverse assemblages of silicoflagellates. Approximately 155 species and separate morphotypes are described from the Paleogene and earliest Neogene. New taxa described from Leg 114 sediments include Bachmannocena vetula n. sp., Corbisema animoparallela n. sp., Corbisema camara n. sp., Corbisema constricta spinosa n. subsp., Corbisema delicata n. sp., Corbisema hastata aha n. subsp., Corbisema praedelicata n. sp., Corbisema scapana n. sp., Corbisema triacantha lepidospinosa n. subsp., Dictyocha deflandreifurtivia n. subsp., Naviculopsis biapiculata nodulifera n. subsp., Naviculopsis cruciata n. sp., Naviculopsis pandalata n. sp., Naviculopsis primativa n. sp., and Naviculopsis trispinosa eminula n. subsp. Taxonomic revisions were made to the following taxa: Corbisema constricta constricta emended, Corbisema disymmetrica crenulata n. comb., Corbisema jerseyensis emended, and Distephanus antarcticus n. comb. Silicoflagellate assemblages from the Paleogene and earliest Neogene of Holes 698A, 699A, 700B, 702B, and 703A are the basis of a silicoflagellate zonation spanning the interval from 63.2 to 22.25 Ma. Silicoflagellate zones recognized in this interval include the Corbisema hastata hastata Zone, Corbisema hastata aha Zone, Dictyocha precarentis Zone, Naviculopsis constricta Zone, Naviculopsis foliacea Zone, Bachmannocena vetula Zone, Dictyocha grandis Zone, Naviculopsis pandalata Zone, Naviculopsis constricta-Bachmannocena paulschulzii Zone, Bachmannocena paulschulzii Zone, Naviculopsis trispinosa Zone with subzones a and b, Corbisema archangelskiana Zone, Naviculopsis biapiculata Zone, Distephanus raupii Zone, Distephanus raupii-Corbisema triacantha Zone, and Corbisema triacantha mediana Zone.

Miocene strontium isotope record of DSDP Hole 30-289

A composite strontium isotopic seawater curve was constructed for the Miocene between 24 and 6 Ma by combining 87Sr/86Sr measurements of planktonic foraminifera from Deep Sea Drilling Project sites 289 and 588. Site 289, with its virtually continuous sedimentary record and high sedimentation rates (26 m/m.y.), was used for constructing the Oligocene to mid-Miocene part of the record, which included the calibration of 63 biostratigraphic datums to the Sr seawater curve using the timescale of Cande and Kent (1992 doi:10.1029/92JB01202). Across the Oligocene/Miocene boundary, a brief plateau occurred in the Sr seawater curve (87Sr/86Sr values averaged 0.70824) which is coincident with a carbon isotopic maximum (CM-O/M) from 24.3 to 22.6 Ma. During the early Miocene, the strontium isotopic curve was marked by a steep rise in 87Sr/86Sr that included a break in slope near 19 Ma. The rate of growth was about 60 ppm/m.y. between 22.5 and 19.0 Ma and increased to over 80 ppm/m.y. between 19.0 and 16 Ma. Beginning at ~16 Ma (between carbon isotopic maxima CM3 and CM4 of Woodruff and Savin (1991 doi:10.1029/91PA02561)), the rate of 87Sr/86Sr growth slowed and 87Sr/86Sr values were near constant from 15 to 13 Ma. After 13 Ma, growth in 87Sr/86Sr resumed and continued until ~9 Ma, when the rate of 87Sr/86Sr growth decreased to zero once again. The entire Miocene seawater curve can be described by a high-order function, and the first derivative (d87Sr/86Sr/dt) of this function reveals two periods of increased slope. The greatest rate of 87Sr/86Sr change occurred during the early Miocene between ~20 and 16 Ma, and a smaller, but distinct, period of increased slope also occurred during the late Miocene between ~12 and 9 Ma. These periods of steepened slope coincide with major phases of uplift and denudation of the Himalayan-Tibetan Plateau region, supporting previous interpretations that the primary control on seawater 87Sr/86Sr during the Miocene was related to the collision of India and Asia. The rapid increase in 87Sr/86Sr values during the early Miocene from 20 to 16 Ma imply high rates of chemical weathering and dissolved riverine fluxes to the oceans. In the absence of another source of CO2, these high rates of chemical weathering should have quickly resulted in a drawdown of atmospheric CO2 and climatic cooling through a reversed greenhouse effect. The paleoclimatic record, however, indicates a warming trend during the early Miocene, culminating in a climatic optimum between 17 and 14.5 Ma. We suggest that the high rates of chemical erosion and warm temperatures during the climatic optimum were caused by an increase in the contribution of volcanic CO2 from the eruption of the Columbia River Flood Basalts (CRFB) between 17 and 15 Ma. The decrease in the rate of CRFB eruptions at 15 Ma and the removal of atmospheric carbon dioxide by increased organic carbon burial in Monterey deposits eventually led to cooling and increased glaciation between ~14.5 and 13 Ma. The CRFB hypothesis helps to explain the significant time lag between the onset of increased rates of organic carbon burial in the Monterey at 17.5 Ma (as marked by increased delta13C values) and the climatic cooling and glaciation during the middle Miocene (as marked by the increase in delta18O values), which did not begin until ~14.5 Ma.

Tab. 1: Age of biogene material from the ice margin, Kofoed-Hansen Bræ and Storstrømmen

Early Holocene recession of the ice cover over Germania Land in North-East Greenland 7.5 ka B.P. brought the Inland Ice margin back to a position close to the present. Continued recession after that time lead to the formation of a "Storstrømmen Sound" which separated Germania Land from mainland Greenland in the period from about 6 to 1 ka B.P. The present filling of the approximately 100 km long sound by the glaciers of Storstrømmen and Kofoed-Hansen Bræ must therefore have taken place during the Little lce Age. In an archaeological sense this implies deterioration of the living conditions of Neo-Eskimos compared to those of Palaeo-Eskimos. The neoglacial re-formation and present existence of the glaciers as a Little Ice Age relict may imply a present-day instability in their dynamics, as demonstrated by the pulsations (surge-like behaviour) in the last part of the 20th century. An earlier Little Ice Age advance might possibly have had the same amplitude as that documented from the 20th century but its exact age and character is not known. The glacio-isostatic response of the earth's crust to the variations in the Holocene glacier load implies a relatively slow and slight emergence and subsequent submergence. The shift from emergence to submergence must have taken place between about 2 and 1 ka B.P.

(Table) Specific activities of 137Cs, 90Sr and 239,240Pu in surface waters obtained during cruises BP06-BP09, Indian Ocean

One of the main sources of anthropogenic radionuclides in the ocean is the global fallout resulting from the nuclear tests that had been conducted by the United States, the former Soviet Union, and other countries between 1945 and 1990 mainly in the Northern Hemisphere. The most extensive fallout was observed in the middle latitudes of the Northern Hemisphere in 1963 immediately after the nuclear tests of 1961-1962 conducted by the United States and the Soviet Union. In 2006-2009, under the auspices of an agreement between the Vernadsky Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences and the National Center of Antarctic and Marine Research of the Ministry of Earth Sciences of India, cooperative geological and geochemical investigations were organized in several regions of the Indian Ocean. During these expeditions, the spatial distribution of anthropogenic radionuclides was investigated in the water of the Indian Ocean. The main results of these investigations are reported in this paper.

Lithology of sediments from the Arabian Sea

The role of hotter than ambient plume mantle in the formation of a rifted volcanic margin in the northern Arabian Sea is investigated using subsidence analysis of a drill site located on the seismically defined Somnath volcanic ridge. The ridge has experienced >4 km of subsidence since 65 Ma and lies within oceanic lithosphere. We estimate crustal thickness to be 9.5-11.5 km. Curiously <400 m of the thermal subsidence occurred prior to 37 Ma, when subsidence rates would normally be at a maximum. We reject the hypothesis that this was caused by increasing plume dynamic support after continental break-up because the size of the thermal anomalies required are unrealistic (>600°C), especially considering the rapid northward drift of India relative to the Deccan-Réunion hotspot. We suggest that this reflects very slow lithospheric growth, possibly caused by vigorous asthenospheric convection lasting >28 m.y., and induced by the steep continent-ocean boundary. Post-rift slow subsidence is also recognized on volcanic margins in the NE Atlantic and SE Newfoundland and cannot be used as a unique indicator of plume mantle involvement in continental break-up.

What Explains Real and Nominal Exchange Rate Fluctuations? Evidence from SVAR Analysis for India

This study empirically analyzes the sources of the exchange rate fluctuations in India by employing the structural VAR model. The VAR system consists of three variables, i.e., the nominal exchange rate, the real exchange rate, and the relative output of India and a foreign country. Consistent with most previous studies, the empirical evidence demonstrates that real shocks are the main drives of the fluctuations in real and nominal exchange rates, indicating that the central bank cannot maintain the real exchange rate at its desired level over time.

On the approximate parametrization problem of algebraic curves.

The problem of parameterizing approximately algebraic curves and surfaces is an active research field, with many implications in practical applications. The problem can be treated locally or globally. We formally state the problem, in its global version for the case of algebraic curves (planar or spatial), and we report on some algorithms approaching it, as well as on the associated error distance analysis.

Uncertainty Estimation for Performance Evaluation of a Confocal Microscope as Metrology Equipment

Both in industry and research, the quality control of micrometric manufactured parts is based on the measurement of parameters whose traceability is sometimes difficult to guarantee. In some of these parts, the confocal microscopy shows great aptitudes to characterize a measurand qualitatively and quantitatively. The confocal microscopy allows the acquisition of 2D and 3D images that are easily manipulated. Nowadays, this equipment is manufactured by many different brands, each of them claiming a resolution probably not in accord to their real performance. The Laser Center (Technical University of Madrid) has a confocal microscope to verify the dimensions of the micro mechanizing in their own research projects. The present study pretends to confirm that the magnitudes obtained are true and reliable. To achieve this, a methodology for confocal microscope calibration is proposed, as well as an experimental phase for dimensionally valuing the equipment by 4 different standard positions, with its seven magnifications and the six objective lenses that the equipment currently has, in the x–y and z axis. From the results the uncertainty will be estimated along with an effect analysis of the different magnifications in each of the objective lenses.

Activation changes the spectrum but not the diversity of genes expressed by T cells

During activation T cells are thought to change their patterns of gene expression dramatically. To find out whether this is true for T cells activated in animals, the patterns of genes expressed in resting T cells and T cells 8 and 48 hr after activation were examined by using Affymetrix gene arrays. Gene arrays gave accurate comparisons of gene expression in the different cell types because the expression of genes known to vary during activation changed as expected. Of the approximately 6,300 genes assessed by the arrays, about one-third were expressed to appreciable extents in any of the T cells tested. Thus, resting T cells express a surprisingly large diversity of genes. The patterns of gene expression changed considerably within 8 hr of T cell activation but returned to a disposition more like that of resting T cells within 48 hr of exposure to antigen. Not unexpectedly, the activated T cells expressed genes associated with cell division at higher levels than resting T cells. The resting T cells expressed a number of cytokine receptor genes and some genes thought to suppress cell division, suggesting that the state of resting T cells is not a passive failure to respond to extant external stimuli.

Typing of urinary JC virus DNA offers a novel means of tracing human migrations

Although polyomavirus JC (JCV) is the proven pathogen of progressive multifocal leukoencephalopathy, the fatal demyelinating disease, this virus is ubiquitous as a usually harmless symbiote among human beings. JCV propagates in the adult kidney and excretes its progeny in urine, from which JCV DNA can readily be recovered. The main mode of transmission of JCV is from parents to children through long cohabitation. In this study, we collected a substantial number of urine samples from native inhabitants of 34 countries in Europe, Africa, and Asia. A 610-bp segment of JCV DNA was amplified from each urine sample, and its DNA sequence was determined. A worldwide phylogenetic tree subsequently constructed revealed the presence of nine subtypes including minor ones. Five subtypes (EU, Af2, B1, SC, and CY) occupied rather large territories that overlapped with each other at their boundaries. The entire Europe, northern Africa, and western Asia were the domain of EU, whereas the domain of Af2 included nearly all of Africa and southwestern Asia all the way to the northeastern edge of India. Partially overlapping domains in Asia were occupied by subtypes B1, SC, and CY. Of particular interest was the recovery of JCV subtypes in a pocket or pockets that were separated by great geographic distances from the main domains of those subtypes. Certain of these pockets can readily be explained by recent migrations of human populations carrying these subtypes. Overall, it appears that JCV genotyping promises to reveal previously unknown human migration routes: ancient as well as recent.

Cloning and Sequencing of a Protein Involved in Phagosomal Membrane Fusion in Paramecium

An mAb was raised to the C5 phagosomal antigen in Paramecium multimicronucleatum. To determine its function, the cDNA and genomic DNA encoding C5 were cloned. This antigen consisted of 315 amino acid residues with a predicted molecular weight of 36,594, a value similar to that determined by SDS-PAGE. Sequence comparisons uncovered a low but significant homology with a Schizosaccharomyces pombe protein and the C-terminal half of the β-fructofuranosidase protein of Zymomonas mobilis. Lacking an obvious transmembrane domain or a possible signal sequence at the N terminus, C5 was predicted to be a soluble protein, whereas immunofluorescence data showed that it was present on the membranes of vesicles and digestive vacuoles (DVs). In cells that were minimally permeabilized but with intact DVs, C5 was found to be located on the cytosolic surface of the DV membranes. Immunoblotting of proteins from the purified and KCl-washed DVs showed that C5 was tightly bound to the DV membranes. Cryoelectron microscopy also confirmed that C5 was on the cytosolic surface of the discoidal vesicles, acidosomes, and lysosomes, organelles known to fuse with the membranes of the cytopharynx, the DVs of stages I (DV-I) and II (DV-II), respectively. Although C5 was concentrated more on the mature than on the young DV membranes, the striking observation was that the cytopharyngeal membrane that is derived from the discoidal vesicles was almost devoid of C5. Approximately 80% of the C5 was lost from the discoidal vesicle-derived membrane after this membrane fused with the cytopharyngeal membrane. Microinjection of the mAb to C5 greatly inhibited the fusion of the discoidal vesicles with the cytopharyngeal membrane and thus the incorporation of the discoidal vesicle membranes into the DV membranes. Taken together, these results suggest that C5 is a membrane protein that is involved in binding and/or fusion of the discoidal vesicles with the cytopharyngeal membrane that leads to DV formation.

Evolutionary specialization of the nuclear targeting apparatus

The α- and β-karyopherins (Kaps), also called importins, mediate the nuclear transport of proteins. All α-Kaps contain a central domain composed of eight approximately 40 amino acid, tandemly arranged, armadillo-like (Arm) repeats. The number and order of these repeats have not changed since the common origin of fungi, plants, and mammals. Phylogenetic analysis suggests that the various α-Kaps fall into two groups, α1 and α2. Whereas animals encode both types, the yeast genome encodes only an α1-Kap. The β-Kaps are characterized by 14–15 tandemly arranged HEAT motifs. We show that the Arm repeats of α-Kaps and the HEAT motifs of β-Kaps are similar, suggesting that the α-Kaps and β-Kaps (and for that matter, all Arm and HEAT repeat-containing proteins) are members of the same protein superfamily. Phylogenetic analysis indicates that there are at least three major groups of β-Kaps, consistent with their proposed cargo specificities. We present a model in which an α-independent β-Kap progenitor gave rise to the α-dependent β-Kaps and the α-Kaps.

Potential responses of soil organic carbon to global environmental change

Recent improvements in our understanding of the dynamics of soil carbon have shown that 20–40% of the approximately 1,500 Pg of C stored as organic matter in the upper meter of soils has turnover times of centuries or less. This fast-cycling organic matter is largely comprised of undecomposed plant material and hydrolyzable components associated with mineral surfaces. Turnover times of fast-cycling carbon vary with climate and vegetation, and range from <20 years at low latitudes to >60 years at high latitudes. The amount and turnover time of C in passive soil carbon pools (organic matter strongly stabilized on mineral surfaces with turnover times of millennia and longer) depend on factors like soil maturity and mineralogy, which, in turn, reflect long-term climate conditions. Transient sources or sinks in terrestrial carbon pools result from the time lag between photosynthetic uptake of CO2 by plants and the subsequent return of C to the atmosphere through plant, heterotrophic, and microbial respiration. Differential responses of primary production and respiration to climate change or ecosystem fertilization have the potential to cause significant interrannual to decadal imbalances in terrestrial C storage and release. Rates of carbon storage and release in recently disturbed ecosystems can be much larger than rates in more mature ecosystems. Changes in disturbance frequency and regime resulting from future climate change may be more important than equilibrium responses in determining the carbon balance of terrestrial ecosystems.