Magnetic dynamo action in two-dimensional turbulent magneto-hydrodynamics

Two-dimensional magnetohydrodynamic turbulence is explored by means of numerical simulation. Previous analytical theory, based on non-dissipative constants of the motion in a truncated Fourier representation, is verified by following the evolution of highly non-equilibrium initial conditions numerically. Dynamo action (conversion of a significant fraction of turbulent kinetic energy into long-wavelength magnetic field energy) is observed. It is conjectured that in the presence of dissipation and external forcing, a dual cascade will be observed for zero-helicity situations. Energy will cascade to higher wave numbers simultaneously with a cascade of mean square vector potential to lower wave numbers, leading to an omni-directional magnetic energy spectrum which varies as 1/k 3 at lower wave numbers, simultaneously with a buildup of magnetic excitation at the lowest wave number of the system. Equipartition of kinetic and magnetic energies is expected at the highest wave numbers in the system

Differential effectiveness of berry polyphenols as anti-giardial agents

Following previous work on the anti-giardial effect of blueberry polyphenols, a range of polyphenol-rich extracts from berries and other fruits was screened for their ability to kill Giardia duodenalis, an intestinal parasite of humans. Polyphenol-rich extracts were prepared from berries using solid-phase extraction and applied to trophozoites of Giardia duodenalis grown in vitro. All berry extracts caused inhibition at 166 μg gallic acid equivalents (GAE)/ml phenol content but extracts from strawberry, arctic bramble, blackberry and cloudberry were as effective as the currently used drug, metronidazole, causing complete trophozoite mortality in vitro. Cloudberry extracts were found to be the most effective causing effectively complete trophozoite mortality at 66 μg GAE/ml. The polyphenol composition of the more effective berry extracts suggested that the presence of ellagitannins could be an important factor. However, the potency of cloudberry could be related to high ellagitannin content but also to the presence of substantial amounts of unconjugated p-coumaric acid and benzoic acid. These in vitro effects occur at concentrations easily achievable in the gut after berry ingestion and we discuss the likelihood that berry extracts could be effective anti-giardial agents in vivo

Asymmetric synthesis of heterocyclic chloroamines and aziridines by enantioselective protonation of catalytically generated enamines

L.A.M. and J.W.B.F. thank EPSRC for postdoctoral funding (EP/S027165/1; EP/R025754/1). J.W.B.F. thanks the Leverhulme Trust for postdoctoral funding (RPG-2018-362). M.W.A. thanks the University of St Andrews for a PhD studentship.We report a method for the synthesis of chiral vicinal chloroamines via asymmetric protonation of catalytically generatedprochiral chloroenamines using chiral Brønsted acids. The processis highly enantioselective, with the origin of asymmetry and catalystsubstituent effects elucidated by DFT calculations. We show theutility of the method as an approach to the synthesis of a broadrange of heterocycle-substituted aziridines by treatment of thechloroamines with base in a one-pot process, as well as the utility ofthe process to allow access to vicinal diamines.Publisher PDFPeer reviewe

Light induced calcium binding to mangrove PS II particles

AbstractA combination calcium selective and oxygen electrode system was used to measure the Ca2+ and O2 concentrations of a solution surrounding mangrove PS II particles. Concomitant uptake of Ca2+ and oxygen evolution in the light were observed. The Ca2+ bound during the light was released in a subsequent dark period. The Ca2+ binding was dependent on both chlorophyll and Ca2+ concentrations. Up to 3000 Ca2+ were calculated to be bound per reaction centre

Daily Fermented Whey Consumption Alters the Fecal Short-Chain Fatty Acid Profile in Healthy Adults

FUNDING: This study was funded by A.Vogel Bioforce AG, Roggwil, Switzerland. NS was co-funded by the School of Medicine, Medical Sciences and Nutrition (University of Aberdeen) and A.Vogel Bioforce AG. The Rowett Institute (University of Aberdeen) receives financial support from the Scottish Government Rural and Environmental Sciences and Analytical Services (RESAS). ACKNOWLEDGMENTS: We thank all the volunteers which contributed their time and efforts into enrolling and completing the trial. Further, we are grateful for the staff at the Human Nutrition Unit and Analytical Services at the Rowett Institute for supporting the research and assisting when needed. We would like to thank Brennan Martin at the Center for Genome Enabled Biology of Medicine for his assistance in DNA sequencingPeer reviewedPublisher PD

Nunalleq, Stories from the Village of Our Ancestors:Co-designing a multivocal educational resource based on an archaeological excavation

This work was funded by the UK-based Arts and Humanities Research Council through grants (AH/K006029/1) and (AH/R014523/1), a University of Aberdeen IKEC Award with additional support for travel and subsistence from the University of Dundee, DJCAD Research Committee RS2 project funding. Thank you to the many people who contributed their support, knowledge, feedback, voices and faces throughout the project, this list includes members of the local community, colleagues, specialists, students, and volunteers. If we have missed out any names we apologize but know that your help was appreciated. Jimmy Anaver, John Anderson, Alice Bailey, Kieran Baxter, Pauline Beebe, Ellinor Berggren, Dawn Biddison, Joshua Branstetter, Brendan Body, Lise Bos, Michael Broderick, Sarah Brown, Crystal Carter, Joseph Carter, Lucy Carter, Sally Carter, Ben Charles, Mary Church, Willard Church, Daniele Clementi, Annie Cleveland, Emily Cleveland, Joshua Cleveland, Aron Crowell, Neil Curtis, Angie Demma, Annie Don, Julia Farley, Veronique Forbes, Patti Fredericks, Tricia Gillam, Sean Gleason, Sven Haakanson, Cheryl Heitman, Grace Hill, Diana Hunter, Joel Isaak, Warren Jones, Stephan Jones, Ana Jorge, Solveig Junglas, Melia Knecht, Rick Knecht, Erika Larsen, Paul Ledger, Jonathan Lim Soon, Amber Lincoln, Steve Luke, Francis Lukezic, Eva Malvich, Pauline Matthews, Roy Mark, Edouard Masson-MacLean, Julie Masson-MacLean, Mhairi Maxwell, Chuna Mcintyre, Drew Michael, Amanda Mina, Anna Mossolova, Carl Nicolai Jr, Chris Niskanen, Molly Odell, Tom Paxton, Lauren Phillips, Lucy Qin, Charlie Roberts, Chris Rowe, Rufus Rowe,Chris Rowland, John Rundall, Melissa Shaginoff, Monica Shah, Anna Sloan, Darryl Small Jr, John Smith, Mike Smith, Joey Sparaga, Hannah Strehlau, Dora Strunk, Larissa Strunk, Lonny Strunk, Larry Strunk, Robbie Strunk, Sandra Toloczko, Richard Vanderhoek, the Qanirtuuq Incorporated Board, the Quinhagak Dance Group and the staff at Kuinerrarmiut Elitnaurviat. We also extend our thanks to three anonymous reviewers for their valuable comments on our paper.Peer reviewedPublisher PD

Does police size matter?:A review of the evidence regarding restructuring police organisations

Restructuring and merging public sector organisations is often seen as a way to enhance efficiency and efficacy. There is ongoing debate about the impact of police force sizes, structures and mergers as police organisations attempt to adapt to reductions in their budgets and changes in patterns of criminality. The article reviews the evidence regarding key aspects of police reform: finding mixed evidence regarding the links between size and performance, while noting risks that mergers may impair local policing. The article discusses the impact of mergers on protective services, governance and accountability, while also discussing potential risks and opportunities associated with the merger process itself. The review finds significant gaps in the available evidence, and significant opportunities to expand the evidence base on this topic. Given current gaps in the evidence regarding size, efficacy and efficiency, it is important to give due consideration to symbolic and rhetorical aspects of mergers

Volcanic Contribution to Decadal Changes in Tropospheric Temperature

Despite continued growth in atmospheric levels of greenhouse gases, global mean surface and tropospheric temperatures have shown slower warming since 1998 than previously. Possible explanations for the slow-down include internal climate variability, external cooling influences and observational errors. Several recent modelling studies have examined the contribution of early twenty-first-century volcanic eruptions to the muted surface warming. Here we present a detailed analysis of the impact of recent volcanic forcing on tropospheric temperature, based on observations as well as climate model simulations. We identify statistically significant correlations between observations of stratospheric aerosol optical depth and satellite-based estimates of both tropospheric temperature and short-wave fluxes at the top of the atmosphere. We show that climate model simulations without the effects of early twenty-first-century volcanic eruptions overestimate the tropospheric warming observed since 1998. In two simulations with more realistic volcanic influences following the 1991 Pinatubo eruption, differences between simulated and observed tropospheric temperature trends over the period 1998 to 2012 are up to 15% smaller, with large uncertainties in the magnitude of the effect. To reduce these uncertainties, better observations of eruption-specific properties of volcanic aerosols are needed, as well as improved representation of these eruption-specific properties in climate model simulations

Stratospheric variability and tropospheric annular‐mode timescales

Climate models tend to exhibit much too persistent Southern Annular Mode (SAM) circulation anomalies in summer, compared to observations. Theoretical arguments suggest this bias may lead to an overly strong model response to anthropogenic forcing during this season, which is of interest since the largest observed changes in Southern Hemisphere high‐latitude climate over the last few decades have occurred in summer, and are congruent with the SAM. The origin of this model bias is examined here in the case of the Canadian Middle Atmosphere Model, using a novel technique to quantify the influence of stratospheric variability on tropospheric annular‐mode timescales. Part of the model bias is shown to be attributable to the too‐late breakdown of the stratospheric polar vortex, which allows the tropospheric influence of stratospheric variability to extend into early summer. However, the analysis also reveals an enhanced summertime persistence of the model’s SAM that is unrelated to either stratospheric variability or the bias in model stratospheric climatology, and is thus of tropospheric origin. No such feature is evident in the Northern Hemisphere. The effect of stratospheric variability in lengthening tropospheric annular‐mode timescales is evident in both hemispheres. While in the Southern Hemisphere the effect is restricted to late‐spring/early summer, in the Northern Hemisphere it can occur throughout the winter‐spring season, with the seasonality of peak timescales exhibiting considerable variability between different 50 year sections of the same simulation