bluuebunny/crossref_metadata_2025_split huggingface dataset:
The biogeochemical cycling of zinc and zinc isotopes in the North Atlantic Ocean
Authors: Conway Tim M. , John Seth G. 
Published: September 2014

AbstractZinc (Zn) is a marine micronutrient, with an overall oceanic distribution mirroring the major macronutrients, especially silicate. Seawater Zn isotope ratios (δ66Zn) are a relatively new oceanographic parameter which may offer insights into the biogeochemical cycling of Zn. To date, the handful of published studies of seawater δ66Zn show the global deep ocean to be both remarkably homogeneous (approximately +0.5‰) and isotopically heavier than the marine sources of Zn (+0.1 to +0.3‰). Here we present the first high‐resolution oceanic section of δ66Zn, from the U.S. GEOTRACES GA03 North Atlantic Transect, from Lisbon to Woods Hole. Throughout the surface ocean, biological uptake and release of isotopically light Zn, together with scavenging of heavier Zn, leads to large variability in δ66Zn. In the ocean below 1000 m, δ66Zn is generally homogeneous (+0.50 ± 0.14‰; 2 SD), though deviations from +0.5‰ allow us to identify specific sources of Zn. The Mediterranean Outflow is characterized by δ66Zn of +0.1 to +0.3‰, while margin sediments are a source of isotopically light Zn (−0.5 to −0.8‰), which we attribute to release of nonregenerated biogenic Zn. Mid‐Atlantic Ridge hydrothermal vents are also a source of light Zn (close to −0.5‰), though Zn is not transported far from the vents. Understanding the biogeochemical cycling of Zn in the modern ocean begins to address the imbalance between the light δ66Zn signature of marine sources and the globally homogeneous deep oceans (δ66Zn of +0.5‰) on long timescales, with overall patterns pointing to sediments as an important sink for isotopically light Zn throughout the oceans.
Dynamic morphology of gas hydrate on a methane bubble in water: Observations and new insights for hydrate film models
Authors: Warzinski Robert P. , Lynn Ronald , Haljasmaa Igor , Leifer Ira , Shaffer Frank , Anderson Brian J. , Levine Jonathan S. 
Published: September 2014

AbstractPredicting the fate of subsea hydrocarbon gases escaping into seawater is complicated by potential formation of hydrate on rising bubbles that can enhance their survival in the water column, allowing gas to reach shallower depths and the atmosphere. The precise nature and influence of hydrate coatings on bubble hydrodynamics and dissolution is largely unknown. Here we present high‐definition, experimental observations of complex surficial mechanisms governing methane bubble hydrate formation and dissociation during transit of a simulated oceanic water column that reveal a temporal progression of deep‐sea controlling mechanisms. Synergistic feedbacks between bubble hydrodynamics, hydrate morphology, and coverage characteristics were discovered. Morphological changes on the bubble surface appear analogous to macroscale, sea ice processes, presenting new mechanistic insights. An inverse linear relationship between hydrate coverage and bubble dissolution rate is indicated. Understanding and incorporating these phenomena into bubble and bubble plume models will be necessary to accurately predict global greenhouse gas budgets for warming ocean scenarios and hydrocarbon transport from anthropogenic or natural deep‐sea eruptions.
Diagnostics of an artificial relativistic electron beam interacting with the atmosphere
Authors: Marshall R. A. , Nicolls M. , Sanchez E. , Lehtinen N. G. , Neilson J. 
Published: September 2014

AbstractWe use a Monte Carlo model to simulate the interaction of a beam of relativistic (0.5–10 MeV) electrons with the upper atmosphere as they are injected downward from a notional high‐altitude (thermospheric/ionospheric) injection platform. The beam parameters, defined by realistic parameters of a compact linear accelerator, are used to create a distribution of thousands of electrons. Each electron is injected downward from 300 km altitude toward the dense atmosphere, where it undergoes elastic and inelastic collisions, leading to secondary ionization, optical emissions, and X‐rays via bremsstrahlung. In this report we describe the model initialization (i.e., development of the electron distribution), essential features of the Monte Carlo model, and secondary outputs, including optical emissions, X‐ray fluxes, secondary ionization, and backscattered energetic electron fluxes. Optical emissions are propagated to the ground through the lower atmosphere, including the effects of atmospheric absorption and scattering, to estimate the brightness of the emission column for a given beam current and energy. Similarly, X‐ray fluxes are propagated to hypothetical detectors on balloons and satellites. Secondary ionization is used to estimate the radar signal returns from various ground‐based radar facilities. Finally, simulated backscattered electron fluxes are measured at the injection location. The simulation results show that each of these diagnostics should be readily detectable by appropriate instruments.
On the radial evolution of κ distributions of pickup protons in the supersonic solar wind
Authors: Fahr Hans‐Jörg , Fichtner Horst , Scherer Klaus 
Published: September 2014

AbstractIt is well known that (pickup) ions in the inner heliosphere do not maintain Maxwellian distributions but tend to nonequilibrium distributions with extended suprathermal tails. Such states have been classified as quasi‐equilibria which in many cases can well be described by so‐called κ distributions. With the present study we start out from a phase space transport equation for pickup ions in the inner heliosphere that adequately describes the most important processes such as injection, convection, cooling, and diffusion in velocity space. Assuming that the underlying distribution functions are κ distributions, we proceed from this transport equation to a second‐order moment, i.e., pressure equation which represents an ordinary differential equation for the κ parameter as function of heliocentric distance. This strategy allows one to describe the transition from an initial Vasyliunas‐Siscoe distribution to κ distributions with gradually more pronounced suprathermal tails. While the velocity dependence of the velocity diffusion coefficient determines the systematic reduction of the parameter κ, the latter always has the (formal) asymptotic value . This translates into values of 1.5≤κTS≤2.2 in the upstream region of the (upwind) solar wind termination shock that defines the outer validity range of the model.
Rapid grounding line migration induced by internal ice stream variability
Authors: Robel A. A. , Schoof C. , Tziperman E. 
Published: September 2014

AbstractObservations indicate that the grounding line position of West Antarctica is sensitive to both forced and unforced ice stream variabilities. This study endeavors to characterize and understand unforced ice stream variability and associated grounding line migration. We use a flowline ice stream model with an undrained plastic bed, lateral shear stresses, and a stretched grid refined in the grounding zone. This model exhibits parameter space structure and hysteresis behavior similar to simpler ice stream models. Low prescribed temperature at the ice surface or weak geothermal heating produces thermal oscillations between active and stagnant phases. As in previous spatially resolved ice flow models, thermal activation propagates as an “activation wave.” This model's fine resolution of the grounding zone allows for accurate simulations of transient, unforced grounding line migration. Upstream of the grounding zone, horizontal grid spacing of 1 km is required to accurately resolve activation waves. Activation waves induce the grounding line to migrate over 100 km at a rate that can exceed 1 km/yr. This is followed during the active phase by retreat, which then continues for the duration of the stagnant phase. Grounding line retreat is the result of a negative mass balance near the grounding line but is not necessarily associated with negative mass balance for the entire ice stream in our simulations of internal variability. The novel approach and experiments described in this study show that there can be large excursions in grounding line position in the absence of either external forcing or retrograde slopes.
Patterns of local and nonlocal water resource use across the western U.S. determined via stable isotope intercomparisons
Authors: Good Stephen P. , Kennedy Casey D. , Stalker Jeremy C. , Chesson Lesley A. , Valenzuela Luciano O. , Beasley Melanie M. , Ehleringer James R. , Bowen Gabriel. J. 
Published: September 2014

AbstractIn the western U.S., the mismatch between public water demands and natural water availability necessitates large interbasin transfers of water as well as groundwater mining of fossil aquifers. Here we identify probable situations of nonlocal water use in both space and time based on isotopic comparisons between tap waters and potential water resources within hydrologic basins. Our approach, which considers evaporative enrichment of heavy isotopes during storage and distribution, is used to determine the likelihood of local origin for 612 tap water samples collected from across the western U.S. We find that 64% of samples are isotopically distinct from precipitation falling within the local hydrologic basin, a proxy for groundwater with modern recharge, and 31% of samples are isotopically distinct from estimated surface water found within the local basin. Those samples inconsistent with local water sources, which we suggest are likely derived from water imported from other basins or extracted from fossil aquifers, are primarily clustered in southern California, the San Francisco Bay area, and central Arizona. Our isotope‐based estimates of nonlocal water use are correlated with both hydrogeomorphic and socioeconomic properties of basins, suggesting that these factors exert a predictable influence on the likelihood that nonlocal waters are used to supply tap water. We use these basin properties to develop a regional model of nonlocal water resource use that predicts (r2 = 0.64) isotopically inferred patterns and allows assessment of total interbasin transfer and/or fossil aquifer extraction volumes across the western U.S.
The role of gut microbes in satisfying the nutritional demands of adult and juvenile wild, black howler monkeys (Alouatta pigra)
Authors: Amato Katherine R. , Leigh Steven R. , Kent Angela , Mackie Roderick I. , Yeoman Carl J. , Stumpf Rebecca M. , Wilson Brenda A. , Nelson Karen E. , White Bryan A. , Garber Paul A. 
Published: September 2014

ABSTRACTIn all mammals, growth, development, pregnancy, and lactation increase nutritional demands. Although primate field studies tend to focus on shifts in activity and diet as mechanisms to compensate for these demands, differences in digestive efficiency also are likely to be important. Because the gut microbiota can impact host digestive efficiency, we examined differences in activity budget, diet, and the gut microbial community among adult male (N = 4), adult female (N = 4), and juvenile (N = 5) wild black howler monkeys (Alouatta pigra) across a ten‐month period in Palenque National Park, Mexico to determine how adult females and juveniles compensate for increased nutritional demands. Results indicate that adult females and juveniles consumed more protein and energy than adult males. Adult males, adult females, and juveniles also possessed distinct gut microbial communities, unrelated to diet. Juveniles exhibited a gut microbiota characterized by bacteria from the phylum Firmicutes, such as Roseburia and Ruminococcus, and demonstrated high fecal volatile fatty acid content, suggesting increased microbial contributions to host energy balances. Adult females possessed a higher Firmicutes to Bacteroidetes ratio, also suggesting increased energy production, and their gut microbiota was characterized by Lactococcus, which has been associated with folate biosynthesis. On the basis of these patterns, it appears that the gut microbiota differentially contributes to howler monkey nutrition during reproduction and growth. Determining the nutritional and energetic importance of shifts in activity, diet, and the gut microbiota in other nonhuman primate taxa, as well as humans, will transform our understanding of these life history processes and the role of host‐microbe relationships in primate evolution. Am J Phys Anthropol 155:652–664, 2014. © 2014 Wiley Periodicals, Inc.
The influence of body size on adult skeletal age estimation methods
Authors: Merritt Catherine E. 
Published: September 2014

ABSTRACTAccurate age estimations are essential to archaeological and forensic analyses. However, reliability for adult skeletal age estimations is poor, especially for individuals over the age of 40 years. This is the first study to show that body size influences skeletal age estimation. The İşcan et al., Lovejoy et al., Buckberry and Chamberlain, and Suchey‐Brooks age methods were tested on 764 adult skeletons from the Hamann‐Todd and William Bass Collections. Statures ranged from 1.30 to 1.93 m and body masses ranged from 24.0 to 99.8 kg. Transition analysis was used to evaluate the differences in the age estimations. For all four methods, the smallest individuals have the lowest ages at transition and the largest individuals have the highest ages at transition. Short and light individuals are consistently underaged, while tall and heavy individuals are consistently overaged. When femoral length and femoral head diameter are compared with the log‐age model, results show the same trend as the known stature and body mass measurements. The skeletal remains of underweight individuals have fewer age markers while those of obese individuals have increased surface degeneration and osteophytic lipping. Tissue type and mechanical loading have been shown to affect bone turnover rates, and may explain the differing patterns of skeletal aging. From an archaeological perspective, the underaging of light, short individuals suggests the need to revisit the current research consensus on the young mortality rates of past populations. From a forensic perspective, understanding the influence of body size will impact efforts to identify victims of mass disasters, genocides, and homicides. Am J Phys Anthropol 156:35–57, 2015 © 2014 Wiley Periodicals, Inc.
Morphological Restructuring of Myocardium During the Early Phase of Experimental Diabetes Mellitus
Authors: Danilova I.G. , Sarapultsev P.A. , Medvedeva S.U. , Gette I.F. , Bulavintceva T.S. , Sarapultsev A.P. 
Published: September 2014

ABSTRACTThe purpose of this study was to determine the specific features of the morphological restructuring of the myocardium in the early stage of experimental diabetes mellitus (DM). Experimental type 1 DM rat model was developed by intraperitoneal injection of alloxan solution at a dose of 30 mg per 100 g body mass. After 1 month, 3 mL of blood was drawn by heart puncture and the plasma separated by centrifugation for biochemical analysis. Plasma glucose, insulin, and glycosylated haemoglobin in whole blood were determined. Light microscopy and morphometric studies were conducted of histological slices of the hearts of experimental animals. The investigation of heart morphology showed a statistically significant alteration in chamber wall thickness in the right auricle in rats with alloxan‐induced DM. A change in cardiomyocyte diameter in myocardium slices was observed in all chambers of DM rats except for the left ventricle. Average cardiomyocyte diameter in rats with experimental DM increased by 26.6% and 15.5% in the right auricle and right ventricle, respectively, while average cardiomyocyte diameter in the left auricle decreased by 20.8%. Histological investigation of the heart following alloxan injection demonstrated, under the epicardium, distended vessels of the venous collecting microcirculatory system. Aggregation and agglutination of red blood cells and endothelial cell destruction were found in some vessels. In the early stage of DM development, structural alterations in the microcirculatory channels and myocardiocytes can be observed in the heart. These structural alterations were most evident in the right chambers of the heart. Anat Rec, 298:396–407, 2015. © 2014 Wiley Periodicals, Inc.
KCa1.1 Inhibition Attenuates Fibroblast‐like Synoviocyte Invasiveness and Ameliorates Disease in Rat Models of Rheumatoid Arthritis
Authors: Tanner Mark R. , Hu Xueyou , Huq Redwan , Tajhya Rajeev B. , Sun Liang , Khan Fatima S. , Laragione Teresina , Horrigan Frank T. , Gulko Pércio S. , Beeton Christine 
Published: September 2014

ObjectiveFibroblast‐like synoviocytes (FLS) participate in joint inflammation and damage in rheumatoid arthritis (RA) and its animal models. The purpose of this study was to define the importance of KCa1.1 (BK, Maxi‐K, Slo1, KCNMA1) channel expression and function in FLS and to establish these channels as potential new targets for RA therapy.MethodsWe compared KCa1.1 expression levels in FLS from rats with pristane‐induced arthritis (PIA) and in FLS from healthy rats. We then used ex vivo functional assays combined with small interfering RNA–induced knockdown, overexpression, and functional modulation of KCa1.1 in PIA FLS. Finally, we determined the effectiveness of modulating KCa1.1 in 2 rat models of RA, moderate PIA and severe collagen‐induced arthritis (CIA).ResultsWe found that PIA FLS expressed the KCa1.1 channel as their major potassium channel, as has been found in FLS from patients with RA. In contrast, FLS from healthy rats expressed fewer of these channels. Inhibiting the function or expression of KCa1.1 ex vivo reduced proliferation and invasive properties of, as well as protease production by, PIA FLS, whereas opening native KCa1.1 or overexpressing the channel enhanced the invasiveness of both FLS from rats with PIA and FLS from healthy rats. Treatment with a KCa1.1 channel blocker at the onset of clinical signs stopped disease progression in the PIA and CIA models, reduced joint and bone damage, and inhibited FLS invasiveness and proliferation.ConclusionOur results demonstrate a critical role of KCa1.1 channels in the regulation of FLS invasiveness and suggest that KCa1.1 channels represent potential therapeutic targets in RA.
NPT1/SLC17A1 Is a Renal Urate Exporter in Humans and Its Common Gain‐of‐Function Variant Decreases the Risk of Renal Underexcretion Gout
Authors: Chiba Toshinori , Matsuo Hirotaka , Kawamura Yusuke , Nagamori Shushi , Nishiyama Takashi , Wei Ling , Nakayama Akiyoshi , Nakamura Takahiro , Sakiyama Masayuki , Takada Tappei , Taketani Yutaka , Suma Shino , Naito Mariko , Oda Takashi , Kumagai Hiroo , Moriyama Yoshinori , Ichida Kimiyoshi , Shimizu Toru , Kanai Yoshikatsu , Shinomiya Nariyoshi 
Published: September 2014

ObjectiveSerum uric acid (SUA) levels in humans are mainly regulated by urate transporters. Recent genome‐wide association studies suggested that common variants of the human sodium‐dependent phosphate cotransporter type 1 gene (NPT1/SLC17A1) influence SUA. NPT1 has been reported to mediate urate transport, but its physiologic role in regulating SUA in humans remains unclear. Furthermore, the findings of replication studies of the relationship between NPT1 variants and gout have been inconsistent. The aims of this study were to investigate the effect of NPT1 on gout and to determine its physiologic role.MethodsFive hundred forty‐five male Japanese patients with gout and 1,115 male Japanese control subjects were genotyped for rs1165196 (I269T), a common missense variant in NPT1. Analyses of the association between rs1165196 and gout were then conducted, focusing especially on renal underexcretion (RUE) gout. Immunohistochemical analysis and functional analysis using Xenopus oocytes were also performed.ResultsSingle‐nucleotide polymorphism rs1165196 significantly decreased the risk of RUE gout (odds ratio 0.73, P = 0.031) but did not confer a risk for all gout (P = 0.123). The immunohistochemical analysis revealed that human NPT1 is localized to the apical membrane of the renal proximal tubule. The functional analysis using Xenopus oocyte expression systems showed that rs1165196 increases NPT1‐mediated urate export.ConclusionThis study showed that NPT1 is a urate exporter located in the renal proximal tubule in humans, and that its common gain‐of‐function variant, rs1165196, causes RUE gout, a major subtype of gout. These findings enable us to deepen our understanding of the physiologic role of NPT1 as a renal urate exporter as well as its pathophysiologic role in gout.
On the transition to 3D modes for channel flow past a square cylinder
Authors: Madhavan S. , Al‐Jahmany Yarub Y. , Minev P.D. , Nandakumar K. 
Published: September 2014

AbstractWe consider the case of transient three‐dimensional, incompressible and isothermal channel flow of a newtonian fluid past a symmetrically confined obstacle of square cross section at zero incidence. The blockage ratio (ratio of cylinder diameter to channel width) is fixed at 1/4. Results from both Laser Doppler (LDV) experiments and direct simulations upto Reynolds numbers have been reported.Starting from the onset of instability (), close examination of the apparent region of influence that envelopes the cylinder reveals a clear vortex shedding signature which extends up to about three diameters upstream. While the fundamental vortex shedding frequency displays a fairly steady monotonic increase with Reynolds number, the Strouhal number (St) shows an inflexion point around . No signs of hysteresis were detected around this region. Furthermore, incommensurate harmonics observed for Reynolds numbers in the range suggest a quasi‐periodic transition to three‐dimensionality. This is shown to be followed by an intermediate periodic window starting around . Results from direct simulations performed using OpenFOAM (the Open Source CFD Toolbox) are used not only to enhance confidence in the accuracy of the reported LDV measurements, but also to help explain the observed phenomena through frequency power spectra and spanwise velocity correlations. Finally, it is concluded that only a parametric variation of transverse and spanwise blockage ratios can bring closure to the subject of bluff‐body wake transitions.