488 research outputs found

    Distribution of carbonate in surface sediments of the Pacific Ocean

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    The distribution of carbonate on the floor of the Pacific has been remapped on the basis of 1313 points from 80 references stored in the World Ocean Sediment Data Bank of Scripps Institution of Oceanography. Percent distribution maps and carbonate versus depth diagrams generally agree with previously published information and reflect the major controlling factors of carbonate sedimentation (depth, hydrography, fertility, and sedimentary processes). While carbonate distributions are of limited use in attempting to construct dissolution profiles, major trends are identifiable. In particular, the degree of lowering of the equatorial calcite compensation depth (CCD) together with an estimate of the differences in supply rates between the equator and the subtropical gyre can be used to estimate dissolution rate increase below the lysocline. There is considerable variation in the sharpness of the ‘CCD transition’ a concept defined here. This variation is thought to reflect both geographic differences in dissolution rate gradients and redeposition processes (carbonate, deep-sea sediments, calcite, and compensation depth)

    Ontong Java Plateau, Leg 130: Synopsis of major drilling results

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    Sixteen holes were drilled at five sites on the northeastern flank of Ontong Java Plateau during Leg 130 (Sites 803 through 807). All of these sites are near the equator, but are at different depths (803: 02°26.0\u27N, 3410 m; 804: 01°00.3\u27N, 3861 m; 805: 01°13.7\u27N, 3188 m; 806: 00°19.1\u27N, 2520 m; and 807: 03°36.4\u27N, 2805 m). One of our goals was to obtain a depth transect of Neogene carbonate deposition for reconstructing the history of ocean climate, chemistry, and productivity, and for understanding the origin of acoustic reflectors. Another goal was to achieve considerable penetration into basement for elucidating the origin of the plateau. All sites yielded multiple Neogene sequences, which were cored using the advanced hydraulic piston corer (APC) to the ooze-chalk transition (10-14 Ma) and with the extended core barrel (XCB) below that. Sites 803 and 807 were drilled to basement and yielded incomplete Paleogene and Cretaceous sections. Penetration into basement was 25 m at Site 803 and 149 m at Site 807; 98 m of basalt was recovered. In all, we cored 5889 m, taking 639 cores. Of the record 4822 m recovered, 55% was taken with the APC, 39% with the XCB, and 6% with the rotary core barrel (RCB). All sites except Site 804 were logged. Neogene sedimentation rates were found to vary by more than a factor of 2, with a striking maximum in the latest Miocene to early Pliocene and a strong minimum in the Pleistocene. Fluctuations in carbonate content on the millionyear scale are highly coherent among depths over the last 12 m.y., perhaps less so before that. Many acoustic reflectors appear synchronous with carbonate reduction events (CREs) and other paleoceanographic events. Other reflectors are tied to diagenesis (e.g., the ooze-chalk transformation, which is diachronous). Recovery of the Cretaceous/Tertiary (K/T) boundary at Sites 803 and 807 demonstrates the presence of a deep carbonate-compensation depth (CCD) across the transition: one sequence is calcareous, the other is not. Because the K/T sections occur below and above major hiatuses, we postulate that special conditions for preservation existed during the transition. In addition, there is evidence of volcanic activity at that time. The basalts cored at Sites 803 and 807 are predominantly olivine-bearing and were erupted during the mid-Cretaceous. At Site 807, pillow lavas buried sediments. One thick flow (at about 28 m) was penetrated here, apparently a flood basalt. Magnetic paleolatitudes suggest that the Ontong Java Plateau has moved coherently with the Pacific Plate since the Early Cretaceous

    Adipogenic and energy metabolism gene networks in longissimus lumborum during rapid post-weaning growth in Angus and Angus × Simmental cattle fed high-starch or low-starch diets

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    <p>Abstract</p> <p>Background</p> <p>Transcriptional networks coordinate adipocyte differentiation and energy metabolism in rodents. The level of fiber and starch in diets with adequate energy content fed to young cattle has the potential to alter intramuscular adipose tissue development in skeletal muscle. Post-weaning alterations in gene expression networks driving adipogenesis, lipid filling, and intracellular energy metabolism provide a means to evaluate long-term effects of nutrition on longissimus muscle development across cattle types.</p> <p>Results</p> <p><it>Longissimus lumborum </it>(LL) from Angus (n = 6) and Angus × Simmental (A × S; n = 6) steer calves (155 ± 10 days age) fed isonitrogenous high-starch (HiS; 1.43 Mcal/kg diet dry matter; n = 6) or low-starch (LoS; 1.19 Mcal/kg diet dry matter; n = 6) diets was biopsied at 0, 56, and 112 days of feeding for transcript profiling of 31 genes associated with aspects of adipogenesis and energy metabolism. Intake of dietary energy (9.44 ± 0.57 Mcal/d) across groups during the study did not differ but feed efficiency (weight gain/feed intake) during the first 56 days was greater for steers fed HiS. Expression of <it>PPARG </it>increased ca. 2-fold by day 56 primarily due to HiS in A × S steers. Several potential <it>PPARG</it>-target genes (e.g., <it>ACACA</it>, <it>FASN</it>, <it>FABP4</it>, <it>SCD</it>) increased 2.5-to-25-fold by day 56 across all groups, with responses (e.g., <it>FASN</it>, <it>FABP4</it>) being less pronounced in A × S steers fed LoS. This latter group of steers had markedly greater blood plasma glucose (0.99 vs. 0.79 g/L) and insulin (2.95 vs. 1.17 ÎŒg/L) by day 112, all of which were suggestive of insulin resistance. Interactions were observed for <it>FABP4</it>, <it>FASN</it>, <it>GPAM</it>, <it>SCD</it>, and <it>DGAT2</it>, such that feeding A × S steers high-starch and Angus steers low-starch resulted in greater fold-changes by day 56 or 112 (<it>GPAM</it>). Marked up-regulation of <it>INSIG1 </it>(4-to-8-fold) occurred throughout the study across all groups. <it>SREBF1 </it>expression, however, was only greater on day 112 namely due to LoS in A × S steers. The lipogenic transcription factor <it>THRSP </it>was 6-to-60-fold greater by day 56 primarily due to HiS in A × S steers, constituting the greatest response among all genes.</p> <p>Conclusion</p> <p>Results involving gene markers of mature adipocytes (e.g., <it>PPARG</it>, <it>THRSP</it>, <it>SCD</it>) provided evidence of intramuscular adipose tissue differentiation during the early portion of the growing phase. The resulting gene networks underscored a central role for <it>PPARG </it>in controlling transcription of genes which are known to co-ordinately regulate adipocyte differentiation and lipid filling in non-ruminants. Unlike rodents, <it>INSIG1 </it>appears to play an important role in cattle muscle adipogenesis. We propose that a network of transcription regulators and nuclear receptors including <it>PPARG</it>-target genes,<it> INSIG1</it>, and <it>THRSP</it>, coordinate activation of adipocyte differentiation and lipid filling at an early age.</p

    Hydrographic Variability of Southeastern United States Shelf and Slope Waters During the Genesis of Atlantic Lows Experiment: Winter 1986

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    Continental shelf waters are particularly responsive to winter storm events mainly because of their shallow depths. Those of the southeastern United States (the South Atlantic Bight (SAB)) are especially responsive because they are broad and shallow. Also, the Gulf Stream serves as a continual source of warm water at the outer boundary. Thus the SAB receives strong meteorological (wind stress and heat loss) and oceanographic (advective) forcing. During the Genesis of Atlantic Lows Experiment (GALE) the response of shelf waters to winter storm events and Gulf Stream forcing was observed. The mean conditions showed a mixed water column with areas of stratification near the coast and at the shelf break. The nearshore area was stratified only during weak offshore winds, and the shelf break area was stratified during southward winds with accompanying onshore Ekman flow. On the inner shelf, advective buoyancy flux was similar in value to heat flux buoyancy and the buoyancy equivalent of wind mixing. Over the shelf break the advective buoyancy flux was 4 times the other forms of buoyancy flux and controlled the observed potential energy variability. A simple box model heat budget used to separate the effect of Gulf Stream eddies and meanders, and Ekman flow and air‐sea heat exchange on the shelf heat content showed that the observed heat content variability was caused by intrusion of Gulf Stream water. The intrusions may be caused either by onshore Ekman flow during southward winds or Gulf Stream meander events

    Guidance of sentinel lymph node biopsy decisions in patients with T1-T2 melanoma using gene expression profiling.

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    AIM: Can gene expression profiling be used to identify patients with T1-T2 melanoma at low risk for sentinel lymph node (SLN) positivity? PATIENTS & METHODS: Bioinformatics modeling determined a population in which a 31-gene expression profile test predicted \u3c5% SLN positivity. Multicenter, prospectively-tested (n = 1421) and retrospective (n = 690) cohorts were used for validation and outcomes, respectively. RESULTS: Patients 55-64 years and ≄65 years with a class 1A (low-risk) profile had SLN positivity rates of 4.9% and 1.6%. Class 2B (high-risk) patients had SLN positivity rates of 30.8% and 11.9%. Melanoma-specific survival was 99.3% for patients ≄55 years with class 1A, T1-T2 tumors and 55.0% for class 2B, SLN-positive, T1-T2 tumors. CONCLUSION: The 31-gene expression profile test identifies patients who could potentially avoid SLN biopsy

    Limits To The Use Of Threatened Species Lists

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    Threatened species lists are designed primarily to provide an easily understood qualitative estimate of risk of extinction. Although these estimates of risk can be accurate, the lists have inevitably become linked to several decision-making processes. There are four ways in which such lists are commonly used: to set priorities for resource allocation for species recovery; to inform reserve system design; to constrain development and exploitation; and to report on the state of the environment. The lists were not designed for any one of these purposes, and consequently perform some of them poorly. We discuss why, if and how they should be used to achieve these purposes

    The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

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    The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

    Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas

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    This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin
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