Water column barium sulfate dissolution and shielding by organic matter aggregates: Implications for the pelagic barite proxy

T.L. was partially supported by a U.S. Department of Defense National Defense Science and Engineering Graduate Student Fellowship and a Ruth Newmark Scholarship from the UCSD Friends of the International Center. M. G. was supported by the Triton Research and Experiential Learning Scholars program. The authors thank Benjamin Gruber, Cecilia de la Prada, and Dr. Erica Ferrer and for their valuable assistance.Pelagic barite (BaSO4) and related proxies are useful tools for reconstructing the marine carbon cycle. The factors controlling pelagic barite dissolution in the ocean water column are poorly understood, which adds uncertainty to Ba-based reconstructions. Here, we conducted static laboratory incubations to test the sensitivity of barium sulfate dissolution rate to a range of commonly occurring seawater pH, salinity, and temperature conditions. We observed relatively rapid dissolution rates ranging from 1.7 & PLUSMN; 0.4 to 3.4 & PLUSMN; 0.8 pg BaSO4 day-1 for these experiments, and we did not observe statistically significant differences in the rate of dissolution with varying pH, salinity, or temperature. The slowest dissolution rate observed in these experiments suggests that an average barium sulfate crystal would survive in the ocean water column just 6.2 & PLUSMN; 0.3 days. We estimate that an average isolated pelagic barite crystal would take 67 years to sink down through the water column, so our experiments imply that solitary pelagic barite crystals do not survive this transit. We conducted an additional experiment on a roller table to assess the impact of organic matter aggregates on barium sulfate dissolution. Free barium sulfate crystals incubated on the roller table dissolved even more rapidly than crystals in the static experiment (19 & PLUSMN; 7 pg BaSO4 day � 1), but barium sulfate crystals incubated with organic matter aggregates showed little sign of dissolution over time. Our findings suggest that organic matter aggregates play a vital role in shielding pelagic barite from dissolution in the water column. This implies that pelagic barite in ocean sediments records the arrival of organic detritus to the seafloor, not just barite crystal formation in sinking organic matter in the upper water column. Additional work is needed to determine which aspects of the marine carbon cycle the pelagic barite proxy captures.U.S. Department of Defense National Defense Science and Engineering Graduate Student FellowshipUCSD Friends of the International CenterTriton Research and Experiential Learning Scholars progra

Barriers to the use of intrauterine devices among healthcare professionals: Evidence against misconceptions. [Barreras al uso de los dispositivos intrauterinos entre los profesionales sanitarios: evidencia frente a creencias erróneas.]

Long-acting reversible contraception (LARC) refers to highly effective methods that are suitable for most women. Despite being the best known long-acting reversible contraception methods, the copper intrauterine device (Cu-IUD) and the hormonal (levonorgestrel) device (LNG-IUD) are used by only 6.9% of women of childbearing age in Spain who use any method of contraception. This may be a consequence of barriers to the use of IUDs among health professionals that affect young and/or nulliparous women in particular. The present review addresses available scientific evidence regarding the main factors creating barriers to the use of intrauterine devices. These factors include possible difficulties during insertion and associated pain, the risk of perforation during the insertion or of expulsion once inserted, the effects on dysmenorrhoea and on menstrual bleeding pattern, the risk of ectopic pregnancy or of pelvic inflammatory disease, the speed of recovery of fertility after removal, the impact of price, and the cost-benefit ratio of intrauterine devices. It also addresses the barrier that results from possible rejection of intrauterine devices by women owing to misconceptions.post-print417 K

Soil pH effects on the Toxicity of zinc oxide nanoparticles to soil bacterial communities.

The environmental levels of ZnO nanoparticles (nZnO) are increasing continually given the widespread and expanding applications of this material. Soil pH appears to be one of the key factors affecting the behavior and toxicity of metal nanoparticles in soi

Fate and effects of uncoated ZnO nanoparticles on nine crops exposed in two agricultural soils, a calcareous and an acidic soil.

The nanotechnology has a wide range of applications including those that deliberately release nanoparticles (NPs) into the environment. The use of nanoformulations containing agrochemicals to soils provides an efficient way to apply pesticides and fertilizers in a controlled mode. The zinc oxide nanoparticles (ZnO NPs) are of particular interest due to their increasing incorporation into agricultural products

Toxicity of ZnO nanoparticles, ZnO bulk and ZnCl2 on earthworms in a spiked natural soil and toxicological effects of leachates on aquatic organisms

The present study assessed the uptake and toxicity of ZnO nanoparticles (NPs), ZnO bulk, and ZnCl2 salt in earthworms in spiked agricultural soils. In addition, the toxicity of aqueous extracts to Daphnia magna and Chlorella vulgaris was analyzed to determine the risk of these soils to the aquatic compartment. We then investigated the distribution of Zn in soil fractions to interpret the nature of toxicity. Neither mortality nor differences in earthworm body weight were observed compared with the control. The most sensitive end point was reproduction. ZnCl2 was notably toxic in eliminating the production of cocoons. The effects induced by ZnO-NPs and bulk ZnO on fecundity were similar and lower than those of the salt. In contrast to ZnO bulk, ZnO-NPs adversely affected fertility. The internal concentrations of Zn in earthworms in the NP group were greater than those in the salt and bulk groups, although bioconcentration factors were consistently <1. No relationship was found between toxicity and internal Zn amounts in earthworms. The results from the sequential extraction of soil showed that ZnCl2 displayed the highest availability compared with both ZnO. Zn distribution was consistent with the greatest toxicity showed by the salt but not with Zn body concentrations. The soil extracts from both ZnO-NPs and bulk ZnO did not show effects on aquatic organisms (Daphnia and algae) after short-term exposure. However, ZnCl2 extracts (total and 0.45-μm filtered) were toxic to Daphnia

Use of contraception by Spanish women after delivery. [Hábitos anticonceptivos tras el parto en las mujeres españolas.]

Objective: To study peripartum use of contraception in women taking long-acting reversible contraceptives (LARCs). Material and methods: Observational, cross-sectional, multicenter, nationwide study of women of reproductive age (18-49 years) attending a gynecology clinic to request LARCs for the first time or to restart treatment. Results: The study population comprised 1,660 patients (1,657 evaluable), with a mean (SD) age of 38.6 (5.7) years. Most already had children (1.9 [0.7] children/patient). During the previous 5 years, 44% of the patients had been pregnant; this was unintended in 10.3% of cases. The main contraceptive method used during the first year after the last delivery was the condom (42.7%), followed by oral contraceptives (16.2%), levonorgestrel-releasing intrauterine devices (7.5%), and the vaginal ring (6.5%). We found that 14.4% of women did not use any contraceptive method during the first year after delivery. Conclusions: LARCs, which are highly effective and easy to apply, continue to be underused after delivery in Spain.post-print677 K

Evaluation of potential of high Si high C steel nanostructured bainite for wear and fatigue applications

The present study is concerned with the potential of high carbon, high silicon steel grades isothermally transformed to bainite at low temperature (<300 C). The first part gives an overview of the design principles, allowing very high strength and ductility to be achieved while minimising transformation duration. Wear and fatigue properties are then investigated for over 10 variants of such materials, manufactured in the laboratory or industrially. The results are discussed against published data. Tensile strengths above 2 GPa are routinely achieved, with, in one case, an exceptional and unprecedented total elongation of over 20%. Bainite plate thickness and retained austenite content are shown to be important factors in controlling the yield strength, though additional, non-negligible parameters remain to be quantified. Rolling-sliding wear performances are found to be exceptional, with as little as 1% of the specific wear rate of conventional 100Cr6 isothermally transformed to bainite. It is suggested that this results from the decomposition of retained austenite in the worn layer, which considerably increases hardness and presumably introduces compressive residual stresses. Fatigue performance was slightly improved over 100Cr6 for one of the two industrially produced materials but significantly lower otherwise. Factors controlling fatigue resistance require further investigations. © 2013 Institute of Materials, Minerals and Mining Published by Maney on behalf of the Institute.Peer Reviewe

Transgenerational effects on development following microplastic exposure in Drosophila melanogaster

Background. Plastic pollution affects all ecosystems, and detrimental effects to animals have been reported in a growing number of studies. However, there is a paucity of evidence for effects on terrestrial animals in comparison to those in the marine realm. Methods. We used the fly Drosophila melanogaster to study the effects that exposure to plastics may have on life history traits and immune response. We reared flies in four conditions: In media containing 1% virgin polyethylene, with no chemical additives; in media supplemented with 1% or 4% polyvinyl chloride, known to have a high content of added chemicals; and control flies in non-supplemented media. Plastic particle size ranged from 23–500 µm. We studied fly survival to viral infection, the length of the larval and pupal stage, sex ratios, fertility and the size of the resultant adult flies. We then performed crossings of F1 flies in non-supplemented media and looked at the life history traits of the F2. Results. Flies treated with plastics in the food media showed changes in fertility and sex ratio, but showed no differences in developmental times, adult size or the capacity to fight infections in comparison with controls. However, the offspring of treated flies reared in non-supplemented food had shorter life cycles, and those coming from both polyvinyl chloride treatments were smaller than those offspring of controls.Fil: Jimenez-Guri, Eva. University of Exeter; Reino Unido. Stazione Zoologica Anton Dhorn; ItaliaFil: Roberts, Katherine E.. University of Exeter; Reino UnidoFil: García, Francisca C.. University of Exeter; Reino UnidoFil: Tourmente, Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Biología Celular y Molecular; ArgentinaFil: Longdon, Ben. University of Exeter; Reino UnidoFil: Godley, Brendan J.. University of Exeter; Reino Unid

First record of the sea cucumber Parastichopus tremulus Gunnerus, 1767 (Echinodermata: Holothuroidea: Aspidochirotida) in the Mediterranean Sea (Alboran Sea, western Mediterranean)

The holothurian Parastichopus tremulus, a species only know from the north-eastern Atlantic, is reported for the first time from the Mediterranean Sea. Five individuals of the species were collected in the vicinity of the Seco de los Olivos sea mount in May 2017 from a bottom trawl sample carried out during the MEDITS trawl survey. Scanning Electron Microscope images of body wall ossicles are supplied to support species identification. Connectivity between Atlantic and Mediterranean populations of P. tremulus is suggested due to the existence of a nearby Atlantic population in the Gulf of Cádiz and the documented presence of abundant holothuroid larvae in the anticyclonic gyre which originates in the Atlantic current entering the Mediterranean, near the Strait of GibraltarPremier signalement du concombre de mer Parastichopus tremulus (Gunnerus, 1767) (Echinodermata : Aspidochirotida) en Méditerranée (Mer d’Alboran, Méditerranée occidentale). L’holothurie Parastichopus tremulus, une espèce connue seulement du nord-est Atlantique, est signalée pour la première fois en Mer Méditerranée. Cinq individus de l’espèce ont été récoltés près du mont sous-marin Seco de los Olivos en mai 2017 d’un échantillon de chalut de fond effectué pendant la campagne de recherche avec chalut MEDITS. Des photographies au microscope électronique à balayage d’osselets de la paroi du corps sont fournies pour valider l’identification de l’espèce. La connectivité entre les populations atlantiques et méditerranéennes de P. tremulus est suggérée en raison de la proximité d’une population atlantique dans le Golfe de Cádiz et de la présence documentée de larves d’holothurie abondantes dans le vortex anticyclonique originaire du courant atlantique entrant en Méditerranée, près du Détroit de GibraltarVersión del edito

Influence of soil pH in the effects of ZnONPs on the antioxidant activities and Zn uptake in three plant species (T aestivum, R. sativus and Z. mays)

In recent years, the study of phytotoxicity of NPs has made rapid progress, but important issues remain to be solved, among them, the role of soil and the importance of the physicochemical soil characteristics for their toxicity and accumulation potential