1,312 research outputs found
Redox heterogeneity in MORB as a function of mantle source
The oxidation state of Earth’s upper mantle both influences and records mantle evolution, but systematic fine-scale variations in upper mantle oxidation state have not previously been recognized in mantle-derived lavas from mid-ocean ridges. Through a global survey of mid-ocean ridge basalt glasses, we show that mantle oxidation state varies systematically as a function of mantle source composition. Negative correlations between Fe3+/ΣFe ratios and indices of mantle enrichment such as 87Sr/86Sr, 208Pb/204Pb, Ba/La, and Nb/Zr ratios reveal that enriched mantle is more reduced than depleted mantle. Because upper mantle carbon may act to simultaneously reduce iron and generate melts that share geochemical traits with our reduced samples, we propose that carbon creates magmas at ridges that are reduced and enriched
The Six Dimensions of Wellness and Cognition in Aging Adults
Objective: Examine how wellness in six dimensions (occupational, social, intellectual, physical, emotional, and spiritual) protects cognition in aging adults. Background: cognitive impairment increases with age. Baby boomers represent a significant percent of the population at risk for cognitive impairment. Cognitive impairment has a negative impact on nursing resources, health care finances, patient mortality, and quality of life. Wellness and prevention is one focus of Institute of Medicine’s vision for the future of nursing. Method: Literature was retrieved from Cumulative Index to Nursing and Allied Health Literature and MEDLINE. Research that examined the affect of wellness in each of the six dimensions on cognition in older adults was included. Results: One or more of the following may protect cognition in aging: midlife occupation complexity, marriage, social networks, formal education, intellectual activities, physical activity, healthy nutrition, motivational ability, purpose in life, and spirituality. Conclusion: Wellness in one or more of the six dimensions may protect cognition in aging. The cognitive protective benefits may increase when wellness in more than one dimension is demonstrated. High wellness in one dimension may protect cognition by compensating for low wellness in another dimension. The interconnectedness of each of the dimensions signifies the importance of evaluating older adults holistically. Wellness throughout the life span may result in improved cognition in aging. Application: Future research is needed to examine the relationship between the six dimensions of wellness and cognition, and to determine if one dimension of wellness is a significant predictor of cognitive health in aging adults
Cardiorespiratory Fitness Is Inversely Associated With Clustering of Metabolic Syndrome Risk Factors: The Ball State Adult Fitness Program Longitudinal Lifestyle Study
Objective: The focus of this study was the association between the metabolic syndrome (MetSyn) and cardiorespiratory fitness (CRF) defined as maximal oxygen uptake (VO2max). Although previous research has shown a relationship between MetSyn and CRF, most studies are based on less objective measures of CRF and different cardiometabolic risk factor thresholds from earlier guidelines
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Reproductive Coercion and Relationship Abuse Among Adolescents and Young Women Seeking Care at School Health Centers.
ObjectiveTo investigate demographic differences and evaluate how reproductive coercion and relationship abuse influences young females' care-seeking and sexual health behaviors.MethodsWe conducted a secondary analysis of cross-sectional baseline survey data from sexually active female students (aged 14-19 years) who sought care from school health centers. Outcomes included recent (previous 3 months) reproductive coercion, physical or sexual adolescent relationship abuse, and nonpartner sexual violence victimization. Cluster-adjusted χ tests compared demographics and generalized linear mixed models estimated associations among reproductive coercion, adolescent relationship abuse (physical and sexual abuse in romantic relationships), and care-seeking and sexual health behaviors.ResultsOf 550 sexually active high school females, 12% reported recent reproductive coercion and 17% reported physical or sexual adolescent relationship abuse, with no significant demographic differences. Prevalence of recent nonpartner sexual violence was 17%. There were no observed significant differences in care-seeking behaviors among those with recent reproductive coercion compared with those without. Physical or sexual adolescent relationship abuse was associated with increased odds of seeking testing or treatment for sexually transmitted infections (adjusted odds ratio [aOR] 2.08, 95% CI 1.05-4.13). Females exposed to both adolescent relationship abuse and reproductive coercion had higher odds of having a partner who was 5 or more years older (aOR 4.66, 95% CI 1.51-14.4), having two or more recent sexual partners (aOR 3.86, 95% CI 1.57-9.48), and using hormonal contraception only (aOR 3.77, 95% CI 1.09-13.1 vs hormonal methods with condoms).ConclusionAlmost one in eight females experienced recent reproductive coercion. We did not observe significant demographic differences in reproductive coercion. Partner age and number of sexual partners may elevate risk for abusive relationships. Relationship abuse is prevalent among high school students seeking care, with no clear pattern for case identification. By failing to identify factors associated with harmful partner behaviors, our results support universal assessment for reproductive coercion and relationship abuse among high school-aged adolescents, involving education, resources, and harm-reduction counseling to all patients.Clinical trial registrationClinicalTrials.gov, NCT01678378
The influence of magmatic differentiation on the oxidation state of Fe in a basaltic arc magma
Subduction zone basalts are more oxidized than basalts from other tectonic settings (e.g., higher Fe 3 + /∑Fe), and this contrast may play a central role in the unique geochemical processes that generate arc and continental crust. The processes generating oxidized arc magmas, however, are poorly constrained, although they appear inherently linked to subduction. Near-surface differentiation processes unique to arc settings might drive oxidation of magmas that originate in equilibrium with a relatively reduced mantle source. Alternatively, arc magmas could record the oxidation conditions of a relatively oxidized mantle source. Here, we present new measurements of olivine-hosted melt inclusions from a single eruption of Agrigan volcano, Marianas, in order to test the influence of differentiation processes vs. source conditions on the Fe 3 + /∑Fe ratio, a proxy for system oxygen fugacity (fO 2 ). We determined Fe 3 + /∑Fe ratios in glass inclusions using μ-XANES and couple these data with major elements, dissolved volatiles, and trace elements. After correcting for post-entrapment crystallization, Fe 3+ /∑Fe ratios in the Agrigan melt inclusions (0.219 to 0.282), and their modeled fO 2 s (ΔQFM +1.0 to +1.8), are uniformly more oxidized than MORB, and preserve a portion of the evolution of this magma from 5.7 to 3.2 wt.% MgO. Fractionation of olivine ±clinopyroxene ±plagioclase should increase Fe 3+ /∑Fe as MgO decreases in the melt, but the data show Fe 3+ /∑Fe ratios decreasing as MgO decreases below 5 wt.% MgO. The major element trajectories, taken in combination with this strong reduction trend, are inconsistent with crystallization of common ferromagnesian phases found in the bulk Agrigan sample, including magnetite. Rather, decreasing Fe 3+ /∑Fe ratios correlate with decreasing S concentrations, suggesting that electronic exchanges associated with SO 2 degassing may dominate Fe 3+ /∑Fe variations in the melt during differentiation. In the case of this magma, the dominant effect of differentiation on magmatic fO 2 is reduction rather than oxidation. Tracing back Agrigan melts with MgO>5 wt.% (i.e., minimally degassed for S) along a modeled olivine fractionation trend to primary melts in equilibrium with Fo 90 olivine reveals melts in equilibrium with the mantle beneath Agrigan at fO 2 s of ΔQFM +1 to +1.6, significantly more oxidized than current constraints for the mantle beneath midocean ridges
The oxidation state of Fe in MORB glasses and the oxygen fugacity of the upper mantle.
Micro-analytical determination of Fe3+/ΣFe ratios in mid-ocean ridge basalt (MORB) glasses using micro X-ray absorption near edge structure (μ-XANES) spectroscopy reveals a substantially more oxidized upper mantle than determined by previous studies. Here, we show that global MORBs yield average Fe3+/ΣFe ratios of 0.16±0.01 (n=103), which trace back to primary MORB melts equilibrated at the conditions of the quartz-fayalite-magnetite (QFM) buffer. Our results necessitate an upward revision of the Fe3+/ΣFe ratios of MORBs, mantle oxygen fugacity, and the ferric iron content of the mantle relative to previous wet chemical determinations. We show that only 0.01 (absolute, or \u3c10%) of the difference between Fe3+/ΣFe ratios determined by micro-colorimety and XANES can be attributed to the Mössbauer-based XANES calibration. The difference must instead derive from a bias between micro-colorimetry performed on experimental vs. natural basalts. Co-variations of Fe3+/ΣFe ratios in global MORB with indices of low-pressure fractional crystallization are consistent with Fe3+ behaving incompatibly in shallow MORB magma chambers. MORB Fe3+/ΣFe ratios do not, however, vary with indices of the extent of mantle melting (e.g., Na2O(8)) or water concentration. We offer two hypotheses to explain these observations: The bulk partition coefficient of Fe3+ may be higher during peridotite melting than previously thought, and may vary with temperature, or redox exchange between sulfide and sulfate species could buffer mantle melting at ~QFM. Both explanations, in combination with the measured MORB Fe3+/ΣFe ratios, point to a fertile MORB source with greater than 0.3wt.% Fe2O3. © 2011
Decoupling Simulated Annealing From Massive Multiplayer Online Role-Playing Games in RAID
End-users agree that compact technology are an interesting new topic in the field of electri- cal engineering, and physicists concur. In fact, few futurists would disagree with the deploy- ment of Byzantine fault tolerance, demonstrates the structured importance of cryptography. We construct a novel algorithm for the simulation of write-ahead logging (JDL), validating that Byzantine fault tolerance can be made peer-to- peer, classical, and stable. It is often an important mission but is supported by previous work in the field
Determination of Fe\u3csup\u3e3+\u3c/sup\u3e/ΣFe of XANES basaltic glass standards by Mössbauer spectroscopy and its application to the oxidation state of iron in MORB
To improve the accuracy of X-ray absorption near-edge structure (XANES) calibrations for the Fe3 +/ΣFe ratio in basaltic glasses, we reevaluated the Fe3 +/ΣFe ratios of glasses used as standards by Cottrell et al. (2009), and available to the community (NMNH catalog #117393). Here we take into account the effect of recoilless fraction on the apparent Fe3 +/ΣFe ratio measured from room temperature Mössbauer spectra in that original study. Recoilless fractions were determined from Mössbauer spectra collected from 40 to 320 K for one basaltic glass, AII_25, and from spectra acquired at 10 K for the 13 basaltic glass standards from the study of Cottrell et al. (2009). The recoilless fractions, f, of Fe2 + and Fe3 + in glass AII_25 were calculated from variable-temperature Mössbauer spectra by a relative method (RM), based on the temperature dependence of the absorption area ratios of Fe3 + and Fe2 + paramagnetic doublets. The resulting correction factor applicable to room temperature determinations (C293, the ratio of recoilless fractions for Fe3 + and Fe2 +) is 1.125 ± 0.068 (2σ). Comparison of the spectra at 10 K for the 13 basaltic glasses with those from 293 K suggests C293 equal to 1.105 ± 0.015 (2σ). Although the 10 K estimate is more precise, the relative method determination is believed to be more accurate, as it does not depend on the assumption that recoilless fractions are equal at 10 K. Applying the effects of recoilless fraction to the relationship between Mössbauer-determined Fe3 +/ΣFe ratios and revised average XANES pre-edge centroids for the 13 standard glasses allows regression of a new calibration of the relationship between the Fe XANES pre-edge centroid energy and the Fe3 +/ΣFe ratio of silicate glass. We also update the calibration of Zhang et al. (2016) for andesites and present a more general calibration for mafic glasses including both basaltic and andesitic compositions. Recalculation of Fe3 +/ΣFe ratios for the mid-ocean ridge basalt (MORB) glasses analyzed previously by XANES by Cottrell and Kelley (2011) results in an average Fe3 +/ΣFe ratio for MORB of 0.143 ± 0.008 (1σ), taking into account only analytical precision, and 0.14 ± 0.01(1σ), taking into account uncertainty on the value of C293. This revised average is lower than the average of 0.16 ± 0.01 given by Cottrell and Kelley (2011). The revised average oxygen fugacity for MORB based on the database of Cottrell and Kelley (2011) is − 0.18 ± 0.16 log units less than the quartz-fayalite-magnetite buffer of Frost (1991) at 100 kPa (∆ QFM = − 0.18 ± 0.16)
The H I mass function of group galaxies in the ALFALFA survey
We estimate the H i mass function (HIMF) of galaxies in groups based on thousands of ALFALFA (Arecibo Legacy Fast ALFA survey) H i detections within the galaxy groups of four widely used SDSS (Sloan Digital Sky Survey) group catalogues. Although differences between the catalogues mean that there is no one definitive group galaxy HIMF, in general we find that the low-mass slope is flat, in agreement with studies based on small samples of individual groups, and that the 'knee' mass is slightly higher than that of the global HIMF of the full ALFALFA sample. We find that the observed fraction of ALFALFA galaxies in groups is approximately 22 per cent. These group galaxies were removed from the full ALFALFA source catalogue to calculate the field HIMF using the remaining galaxies. Comparison between the field and group HIMFs reveals that group galaxies make only a small contribution to the global HIMF as most ALFALFA galaxies are in the field, but beyond the HIMF 'knee' group galaxies dominate. Finally, we attempt to separate the group galaxy HIMF into bins of group halo mass, but find that too few low-mass galaxies are detected in the most massive groups to tightly constrain the slope, owing to the rarity of such groups in the nearby Universe where low-mass galaxies are detectable with existing H i surveys.© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical SocietyWe acknowledge the work of the entire ALFALFA team for
observing, flagging, and performing signal extraction. We thank
the anonymous referee for their suggestions that helped to improve
this paper. MGJ is supported by a Juan de la Cierva formacion´
fellowship (FJCI-2016-29685) from the Spanish Ministerio de
Ciencia, Innovacion y Universidades (MCIU). MGJ and LVM ´
also acknowledge support from the grants AYA2015-65973-C3-1-
R (MINECO/FEDER, UE) and RTI2018-096228-B-C31 (MCIU).
The research of KMH is supported by the under the European
Union’s Seventh Framework Programme (FP/2007-2013)/ERC
Grant Agreement nr. 291531. EAKA is supported by the WISE
research programme, which is financed by the Netherlands Organisation for Scientific Research (NWO). This work has been supported
by the State Agency for Research of the Spanish MCIU through
the ‘Centro de Excelencia Severo Ochoa’ award to the Instituto
de Astrof´ısica de Andaluc´ıa (SEV-2017-0709). This research was
supported by the Munich Institute for Astro- and Particle Physics
(MIAPP) which is funded by the Deutsche Forschungsgemeinschaft
(DFG, German Research Foundation)Peer reviewe
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