High speed shadowgraphy for the study of liquid drops

The book contains invited lectures and selected contributions presented at the Enzo Levi and XVII Annual Meeting of the Fluid Dynamic Division of the Mexican Physical Society in 2011.This was work was sponsored by EPSRC grant number RG5560

Ionic partition and transport in multi-ionic channels: A Molecular Dynamics Simulation study of the OmpF bacterial porin

We performed all-atom molecular dynamics simulations studying the partition of ions and the ionic current through the bacterial porin OmpF and two selected mutants. The study is motivated by new interesting experimental findings concerning their selectivity and conductance behaviour at neutral pH. The mutations considered here are designed to study the effect of removal of negative charges present in the constriction zone of the wild type OmpF channel (which contains on one side a cluster with three positive residues and on the other side two negatively charged residues). Our results show that these mutations induce an exclusion of cations from the constriction zone of the channel, substantially reducing the flow of cations. In fact, the partition of ions inside the mutant channels is strongly inhomogeneous, with regions containing excess of cations and regions containing excess of anions. Interestingly, the overall number of cations inside the channel is larger than the number of anions in the two mutants, as in the OmpF wild type channel. We found that the differences in ionic charge inside these channels are justified by the differences in electric charge between the wild type OmpF and the mutants, following an electroneutral balance

Quantum Simulation of Spin Chains Coupled to Bosonic Modes with Superconducting Circuits

We propose the implementation of a digital quantum simulation of spin chains coupled to bosonic field modes in superconducting circuits. Gates with high fidelities allows one to simulate a variety of Ising magnetic pairing interactions with transverse field, Tavis-Cummings interaction between spins and a bosonic mode, and a spin model with three-body terms. We analyze the feasibility of the implementation in realistic circuit quantum electrodynamics setups, where the interactions are either realized via capacitive couplings or mediated by microwave resonators.Comment: Chapter in R. S. Anderssen et al. (eds.), Mathematics for Industry 11 (Springer Japan, 2015

Low-level jets over the Arctic Ocean during MOSAiC

We present an annual characterization of low-level jets (LLJs) over the Arctic Ocean using wind profiles from radiosondes launched during the Multidisciplinary drifting Observatory for the Study of Arctic Climate expedition, from October 2019 through September 2020. Our results show LLJs to be common throughout the entire year, with a mean annual frequency of occurrence of more than 40%, a typical height below 400 m, peaking at 120–180 m, and speed between 6 and 14 m s–1. Jet characteristics show some seasonal variability: During winter and the freeze-up period, they are more common and faster, with an average occurrence of 55% and speeds of 8–16 m s–1, while in summer and the transition period, they have a mean occurrence of 46% and speeds of 6–10 m s–1. They have a similar height all year, with a peak between 120 and 180 m. The ERA5 reanalysis shows a similar frequency of occurrence, but a 75 m high bias in altitude, and a small, 0.28 m s–1, slow bias in speed. The height biases are greater in the transition period, more than 130 m, while the bias in speed is similar all year. Examining jets in ERA5 over the full year and whole Arctic Ocean, we find that the frequency of occurrence depends strongly on both the season and the distance to the sea-ice edge

A Unifying View on Recombination Spaces and Abstract Convex Evolutionary Search

This is the author accepted manuscript. The final version is available from Springer via the DOI in this record.Proceedings of EvoCOP 2019 - 19th European Conference on Evolutionary Computation, 24-26 April 2019, Leipzig, GermanyPrevious work proposed to unify an algebraic theory of fitness landscapes and a geometric framework of evolutionary algorithms (EAs). One of the main goals behind this unification is to develop an analytical method that verifies if a problem's landscape belongs to certain abstract convex landscapes classes, where certain recombination-based EAs (without mutation) have polynomial runtime performance. This paper advances such unification by showing that: (a) crossovers can be formally classified according to geometric or algebraic axiomatic properties; and (b) the population behaviour induced by certain crossovers in recombination-based EAs can be formalised in the geometric and algebraic theories. These results make a significant contribution to the basis of an integrated geometric-algebraic framework with which analyse recombination spaces and recombination-based EAs

Biomass-modulated fire dynamics during the last glacial-interglacial transition at the central pyrenees (Spain)

Understanding long-term fire ecology is essential for current day interpretation of ecosystem fire responses. However palaeoecology of fire is still poorly understood, especially at high-altitude mountain environments, despite the fact that these are fire-sensitive ecosystems and their resilience might be affected by changing fire regimes. We reconstruct wildfire occurrence since the Lateglacial (14.7. cal. ka BP) to the Mid-Holocene (6. cal. ka BP) and investigate the climate-fuel-fire relationships in a sedimentary sequence located at the treeline in the Central Spanish Pyrenees. Pollen, macro- and micro-charcoal were analysed for the identification of fire events (FE) in order to detect vegetation post-fire response and to define biomass-fire interactions. mean fire intervals (mfi) reduced since the Lateglacial, peaking at 9-7.7. cal. ka BP while from 7.7 to 6. cal. ka BP no fire is recorded. We hypothesise that Early Holocene maximum summer insolation, as climate forcing, and mesophyte forest expansion, as a fuel-creating factor, were responsible for accelerating fire occurrence in the Central Pyrenees treeline. We also found that fire had long-lasting negative effects on most of the treeline plant communities and that forest contraction from 7.7. cal. ka BP is likely linked to the ecosystem's threshold response to high fire frequencies.This research has been funded by the projects DINAMO (CGL2009-07992) (funding EGPF — grant ref. BES-2010-038593 and MSC), DINAMO2 (CGL2012-33063), ARAFIRE (2012 GA LC 064), GRACCIE-CONSOLIDER (CSD2007-00067). GGR was funded by the Juan de la Cierva Program (grant ref. JCI2009-04345) and JAE-Doc CSIC Program, LLM was supported by a postdoctoral MINT fellowship funded by the Institute for the Environment (Brunel University), AMC is a Ramón y Cajal fellow (ref: RYC-2008-02431), APS holds a grant funded by the Aragon Government (ref. 17030G/5423/480072/14003) and JAE holds a grant funded by the Basque Country Government (BFI-2010-5)

INT reduction is a valid proxy for eukaryotic plankton respiration despite the inherent toxicity of INT and differences in cell wall structure

The reduction of 2-para (iodophenyl)-3(nitrophenyl)-5(phenyl) tetrazolium chloride (INT) is increasingly being used as an indirect method to measure plankton respiration. Its greater sensitivity and shorter incubation time compared to the standard method of measuring the decrease in dissolved oxygen concentration, allows the determination of total and size-fractionated plankton respiration with higher precision and temporal resolution. However, there are still concerns as to the method’s applicability due to the toxicity of INT and the potential differential effect of plankton cell wall composition on the diffusion of INT into the cell, and therefore on the rate of INT reduction. Working with cultures of 5 marine plankton (Thalassiosira pseudonana CCMP1080/5, Emiliania huxleyi RCC1217, Pleurochrysis carterae PLY-406, Scrippsiella sp. RCC1720 and Oxyrrhis marina CCMP1133/5) which have different cell wall compositions (silica frustule, presence/absence of calcite and cellulose plates), we demonstrate that INT does not have a toxic effect on oxygen consumption at short incubation times. There was no difference in the oxygen consumption of a culture to which INT had been added and that of a replicate culture without INT, for periods of time ranging from 1 to 7 hours. For four of the cultures (T. pseudonana CCMP1080/5, P. carterae PLY-406, E. huxleyi RCC1217, and O. marina CCMP1133/5) the log of the rates of dissolved oxygen consumption were linearly related to the log of the rates of INT reduction, and there was no significant difference between the regression lines for each culture (ANCOVA test, F = 1.696, df = 3, p = 0.18). Thus, INT reduction is not affected by the structure of the plankton cell wall and a single INT reduction to oxygen consumption conversion equation is appropriate for this range of eukaryotic plankton. These results further support the use of the INT technique as a valid proxy for marine plankton respiration

Anabolism-Associated Mitochondrial Stasis Driving Lymphocyte Differentiation over Self-Renewal

Regeneration requires related cells to diverge in fate. We show that activated lymphocytes yield sibling cells with unequal elimination of aged mitochondria. Disparate mitochondrial clearance impacts cell fate and reflects larger constellations of opposing metabolic states. Differentiation driven by an anabolic constellation of PI3K/mTOR activation, aerobic glycolysis, inhibited autophagy, mitochondrial stasis, and ROS production is balanced with self-renewal maintained by a catabolic constellation of AMPK activation, mitochondrial elimination, oxidative metabolism, and maintenance of FoxO1 activity. Perturbations up and down the metabolic pathways shift the balance of nutritive constellations and cell fate owing to self-reinforcement and reciprocal inhibition between anabolism and catabolism. Cell fate and metabolic state are linked by transcriptional regulators, such as IRF4 and FoxO1, with dual roles in lineage and metabolic choice. Instructing some cells to utilize nutrients for anabolism and differentiation while other cells catabolically self-digest and self-renew may enable growth and repair in metazoa

Superconducting Sr2RuO4 Thin Films without Out-of-Phase Boundaries by Higher-Order Ruddlesden-Popper Intergrowth

Ruddlesden-Popper (RP) phases (An+1B n O3n+1, n = 1, 2,···) have attracted intensive research with diverse functionalities for device applications. However, the realization of a high-quality RP-phase film is hindered by the formation of out-of-phase boundaries (OPBs) that occur at terrace edges, originating from lattice mismatch in the c-axis direction with the A'B'O3 (n = ∞) substrate. Here, using strontium ruthenate RP-phase Sr2RuO4 (n = 1) as a model system, an experimental approach for suppressing OPBs was developed. By tuning the growth parameters, the Sr3Ru2O7 (n = 2) phase was formed in a controlled manner near the film-substrate interface. This higher-order RP-phase then blocked the subsequent formation of OPBs, resulting in nearly defect-free Sr2RuO4 layer at the upper region of the film. Consequently, the Sr2RuO4 thin films exhibited superconductivity up to 1.15 K, which is the highest among Sr2RuO4 films grown by pulsed laser deposition. This work paves the way for synthesizing pristine RP-phase heterostructures and exploring their unique physical properties

Cross-cultural adaptation of children’s environmental health questionnaires for nursing students in England

Objectives: Children are among the most vulnerable population groups with regard to environmental risks. Nursing students must be fully educated on children’s environmental health as they are in a key position to prevent and reduce the effects of environmental hazards. The main objective of this study was to adapt and validate an English language version of two questionnaires about children’s health and the environment, to assess the knowledge and skills of student nurses in England. Design: Observational cross-sectional study. Setting: A university in Southern England. Method: The study involves translating, adapting and validating the Children’s Environmental Health Knowledge Questionnaire (ChEHK-Q) and the Children’s Environmental Health Skills Questionnaire (ChEHS-Q) with nursing students in England (N = 232). Results: The psychometric characteristics of both questionnaires were strong. Infit and outfit values were close to 1. The reliability values for the items and people were 0.96 and 0.79 for ChEHK-Q and 0.98 and 0.89 for ChEHS-Q, respectively. Only 52 (22.41%) and 77 (33.62%) participants had at least good knowledge and skills, respectively. Higher knowledge and skills were found with respect to the vulnerability of children and identification of environmental risks in the home. Lower levels of knowledge and skills were found with respect to the effects of pesticides and the assessment of neoplastic pollutants. Conclusion: Findings demonstrate deficiencies in nursing competencies related to children’s environmental health. The use of these questionnaires will facilitate improvement in both knowledge and skills related to children’s environmental health among future nurses