1,927 research outputs found

    Calculation of coercivity of magnetic nanostructures at finite temperatures

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    We report a finite temperature micromagnetic method (FTM) that allows for the calculation of the coercive field of arbitrary shaped magnetic nanostructures at time scales of nanoseconds to years. Instead of directly solving the Landau-Lifshitz-Gilbert equation, the coercive field is obtained without any free parameter by solving a non linear equation, which arises from the transition state theory. The method is applicable to magnetic structures where coercivity is determined by one thermally activated reversal or nucleation process. The method shows excellent agreement with experimentally obtained coercive fields of magnetic nanostructures and provides a deeper understanding of the mechanism of coercivity.Comment: submitted to Phys. Rev.

    Marginal Coral Populations: the Densest Known Aggregation of Pocillopora in the Galápagos Archipelago is of Asexual Origin

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    Coral populations at distributional margins frequently experience suboptimal and variable conditions. Recurrent El Niño-Southern Oscillation (ENSO) warming events have caused extensive mortality of reef-building corals in the Eastern Pacific, and particularly impacted branching pocilloporid corals in the Galápagos Islands. Pocillopora spp. were previously more common and formed incipient reefs at several locations in the archipelago but now occur as scattered colonies. Here, we report an unusually concentrated aggregation of colonies and evaluate their current genetic diversity. In particular we focus on a large population of 1614 live Pocillopora colonies found in a volcanic lagoon along the southern shore of Isabela Island. Forty seven colonies were sampled, primarily using a spatially explicit sampling design, and all colonies belonged to Pocillopora mitochondrial open reading frame lineage type 3a. Typing of additional Pocillopora samples (n = 40) from three other islands indicated that this stand is the only known representative of type 3a in the Galápagos Islands. The Isabela Pocillopora type 3a colonies harbored Symbiodinium ITS-2 clade C1d. Multilocus genotyping (n = 6 microsatellites) capable of resolving individual clones indicated that this stand is monogenotypic and thus the high density of colonies is a result of asexual reproduction, likely via fragmentation. Colony size distribution, while an imperfect measure, suggested the stand regrew from remnant colonies that survived the 1997/98 ENSO event but may postdate the 1982/83 ENSO. The community of Pocillopora colonies at Isabela is of particular ecological value due to its high density and support of associated organisms such as fish and benthic invertebrates. The Galapagos Pocillopora corals will continue to provide insights into the genetic structure and population dynamics of marginal coral populations

    Feasibilty of Transcutaneous pCO2 Monitoring During Immediate Transition After Birth\u2014A Prospective Observational Study

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    Background: According to recommendations, non-invasive monitoring during neonatal resuscitation after birth includes heart rate (HR) and oxygen saturation (SpO2). Continuous transcutaneous monitoring of carbon dioxide partial pressure (tcpCO2) may further offer quantitative information on neonatal respiratory status. Objective: We aimed to investigate feasibility of tcpCO2 measurements in the delivery room during immediate neonatal transition and to compare the course of tcpCO2 between stable term and preterm infants. Methods: Neonates without need for cardio-respiratory intervention during immediate transition after birth were enrolled in a prospective observational study. In these term and preterm neonates, we measured HR and SpO2 by pulse oximetry on the right wrist and tcpCO2 with the sensor applied on the left hemithorax during the first 15 min after birth. Courses of tcpCO2 were analyzed in term and preterm neonates and groups were compared. Results: Fifty-three term (gestational age: 38.8 \ub1 0.9 weeks) and 13 preterm neonates (gestational age: 34.1 \ub1 1.5 weeks) were included. First tcpCO2 values were achieved in both groups at minute 4 after birth, which reached a stable plateau after the equilibration phase at minute 9. Mean tcpCO2 values 15 min after birth were 46.2 (95% CI 34.5\u201357.8) mmHg in term neonates and 48.5 (95%CI 43.0\u201354.1) mmHg in preterm neonates. Preterm and term infants did not show significant differences in the tcpCO2 values at any time point. Conclusion: This study demonstrates that tcpCO2 measurement is feasible during immediate neonatal transition after birth and that tcpCO2 values were comparable in stable term and preterm neonates

    "Jane sent me this article, so it must be true!" - How tie strength and emotional tone influence information behavior

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    Fake news are a threat of the information age, yet many factors that determine their spread, such as emotional tone and tie strength, remain under-researched. Responding to calls for research, we developed an experimental study that explains the impact of emotional tone and tie strength in the context of instant messaging. We hypothesize effects on the willingness to fact-check and intention to share, mediated by sender credibility and news believability. Our results will contribute to the academic literature on various levels: we consider the emotional and relational dimensions of fake news sharing. Furthermore, we provide a multidimensional understanding of the emotionality of strong-tie contacts sharing fake news in a seemingly private and safe environment. For policymakers, we provide insights that help detect fake news, and we provide individuals with persuasion knowledge to self-protect against fake news
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