Slow Events Research Articles

Phosphorylation of Deinococcus radiodurans RecA Regulates Its Activity and May Contribute to Radioresistance

Deinococcus radiodurans has a remarkable capacity to survive exposure to extreme levels of radiation that cause hundreds of DNA double strand breaks (DSBs). DSB repair in this bacterium depends on its recombinase A protein (DrRecA). DrRecA plays a pivotal role in both extended synthesis-dependent strand annealing and slow crossover events of DSB repair during the organism's recovery from DNA damage. The mechanisms that control DrRecA activity during the D. radiodurans response to γ radiation exposure are unknown. Here, we show that DrRecA undergoes phosphorylation at Tyr-77 and Thr-318 by a DNA damage-responsive serine threonine/tyrosine protein kinase (RqkA). Phosphorylation modifies the activity of DrRecA in several ways, including increasing its affinity for dsDNA and its preference for dATP over ATP. Strand exchange reactions catalyzed by phosphorylated versus unphosphorylated DrRecA also differ. In silico analysis of DrRecA structure support the idea that phosphorylation can modulate crucial functions of this protein. Collectively, our findings suggest that phosphorylation of DrRecA enables the recombinase to selectively use abundant dsDNA substrate present during post-irradiation recovery for efficient DSB repair, thereby promoting the extraordinary radioresistance of D. radiodurans.

In silico characterization of bimolecular electron transfer reactions: The ferrocene–ferrocenium reaction as a test case

AbstractThe theoretical modeling of chemical reactions in condensed phase still represents an open field of investigation for theoretical–computational chemistry. In this context, we have proposed a methodology (the Perturbed Matrix Method [PMM]), based on the first principles of statistical mechanics and on the use of molecular simulations, which has demonstrated its ability in quantitatively predicting the kinetics and the thermodynamics of chemical reactions in complex atomistic environments. In this study, we demonstrate the features of PMM by modeling the resonant Electron Transfer bimolecular reaction between ferrocene and ferrocenium in solution. The obtained results, despite the adopted approximations and the intrinsic limitations of the approach, are in very good agreement with the experimental data and demonstrate the ability of the method for addressing complex reactions in solution and for evaluating the kinetics of slow events out of the potentialities of the state‐of‐the‐art molecular simulations.

Multivariate study of the dynamics of CO2 reaction with brucite-rich ultramafic mine tailings

Mineral carbonation of a nickel mine tailing (NiMT) was studied using a dual-compartment carbonation cell employing moderate CO2 partial pressures for accelerating carbon uptake and to simulate outdoor temperature conditions prevailing in mining waste disposal sites. Time-dependent X-ray powder diffraction analysis and scanning electron microscopy reveal formation of transitional, metastable porous, flaky magnesium carbonates which subsequently evolved into less porous nesquehonite layers, which are shown to be responsible for surface passivation despite availability of unreacted brucite. However, the reactive cores could be turned into easily accessible regions following ex-foliation of carbonated materials. Moreover, it was demonstrated that slow carbonate nucleation events such as during carbonation of as-received ores may be significantly accelerated by means of carbonate pre-seeding strategies.

A 17 June 2011 polar jet and its presence in the background solar wind

AbstractHigh‐speed jet responses in the polar solar wind are enigmatic. Here we measure a jet response that emanates from the southern polar coronal hole on 17 June 2011 at the extreme speed of over 1200 km/s. This response was recorded from the Sun‐Earth line in Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) and Large Angle and Spectrometric Coronagraph/C2 and both Solar TErrestrial RElations Observatory Extreme Ultraviolet Imager and COR2 coronagraphs when the three spacecraft were situated ~90° from one another. These certify the coronal 3‐D location of the response that is associated with an existing solar plume structure and show its high speed to distances of over 14 RS. This jetting is associated with magnetic flux changes in the polar region as measured by the SDO/Helioseismic and Magnetic Imager instrumentation over a period of several hours. The fastest coronal response observed can be tracked to a time near the period of greatest flux changes and to the onset of the brightest flaring in AIA. This high‐speed response can be tracked directly as a small patch of outward moving brightness in coronal images as in Yu et al. (2014) where three slower events were followed from the perspective of Earth. This accumulated jet response has the largest mass and energy we have yet seen in 3‐D reconstructions from Solar Mass Ejection Imager observations, and its outward motion is certified for the first time using interplanetary scintillation observations. This jet response is surrounded by similar high‐speed patches, but these are smoothed out in Ulysses polar measurements, we speculate about how these dynamic activities relate to solar wind acceleration.

Origin and dynamics of depositionary subduction margins

AbstractHere we propose a new framework for forearc evolution that focuses on the potential feedbacks between subduction tectonics, sedimentation, and geomorphology that take place during an extreme event of subduction erosion. These feedbacks can lead to the creation of a “depositionary forearc,” a forearc structure that extends the traditional division of forearcs into accretionary or erosive subduction margins by demonstrating a mode of rapid basin accretion during an erosive event at a subduction margin. A depositionary mode of forearc evolution occurs when terrigenous sediments are deposited directly on the forearc while it is being removed from below by subduction erosion. In the most extreme case, an entire forearc can be removed by a single subduction erosion event followed by depositionary replacement without involving transfer of sediments from the incoming plate. We need to further recognize that subduction forearcs are often shaped by interactions between slow, long‐term processes, and sudden extreme events reflecting the sudden influences of large‐scale morphological variations in the incoming plate. Both types of processes contribute to the large‐scale architecture of the forearc, with extreme events associated with a replacive depositionary mode that rapidly creates sections of a typical forearc margin. The persistent upward diversion of the megathrust is likely to affect its geometry, frictional nature, and hydrogeology. Therefore, the stresses along the fault and individual earthquake rupture characteristics are also expected to be more variable in these erosive systems than in systems with long‐lived megathrust surfaces.

Transient crustal movement in the northern Izu–Bonin arc starting in 2004: A large slow slip event or a slow back-arc rifting event?

The Izu–Bonin arc lies along the convergent boundary where the Pacific Plate subducts beneath the Philippine Sea Plate. Horizontal velocities of continuous Global Navigation Satellite System stations on the Izu Islands move eastward by up to ~1cm/year relative to the stable part of the Philippine Sea Plate suggesting active back-arc rifting behind the northern part of the arc. Here, we report that such eastward movements transiently accelerated in the middle of 2004 resulting in ~3cm extra movements in 3years. We compare three different mechanisms possibly responsible for this transient movement, i.e. (1) postseismic movement of the 2004 September earthquake sequence off the Kii Peninsula far to the west, (2) a temporary activation of the back-arc rifting to the west dynamically triggered by seismic waves from a nearby earthquake, and (3) a large slow slip event in the Izu–Bonin Trench to the east. By comparing crustal movements in different regions, the first possibility can be shown unlikely. It is difficult to rule out the second possibility, but current evidence support the third possibility, i.e. a large slow slip event with moment magnitude of ~7.5 may have occurred there.

Undersea Data Tie Slow Fault Slip to Tsunami-Causing Quakes

Slow events might help scientists better understand when and why tsunami-generating earthquakes occur.

European DEMO divertor target: Operational requirements and material-design interface

Recently, an integrated program of conceptual design activities for the European DEMO reactor was launched in the framework of the EUROfusion Consortium, where reliable power handling capability was identified as one of the most critical scientific as well as technological challenges for a DEMO reactor. The divertor is the key in-vessel plasma-facing component being in charge of power exhaust and removal of impurity particles. The DEMO divertor target will have to withstand extreme thermal loads where the local peak heat flux is expected to reach up to 20 MW/m2 during slow transient events in DEMO. To assure sufficient heat removal capability of the divertor target against normal and transient operational scenarios under expected cumulative neutron dose of up to 13 dpa is one of the fundamental engineering challenges imposed on target design. To develop the design of the DEMO divertor and related technologies, an R&D work package ‘Divertor’ has been set up in this consortium. The subproject ‘Target Development’ is devoted to the development of the conceptual design and the core technologies of the plasma-facing target. Devising and implementing novel structural heat sink materials (e.g. W/Cu composites) to advanced target design concepts is one of the major objectives of this subproject. In this paper, the underlying design requirements imposed by the envisaged power exhaust goal and the prominent material-design interface issues are discussed. In addition, the candidate design concepts being currently considered are presented together with the related material issues. Finally, the first results achieved so far are presented.

Coupling Protein Dynamics with Proton Transport in Human Carbonic Anhydrase II.

The role of protein dynamics in enzyme catalysis is one of the most highly debated topics in enzymology. The main controversy centers around what may be defined as functionally significant conformational fluctuations and how, if at all, these fluctuations couple to enzyme catalyzed events. To shed light on this debate, the conformational dynamics along the transition path surmounting the highest free energy barrier have been herein investigated for the rate limiting proton transport event in human carbonic anhydrase (HCA) II. Special attention has been placed on whether the motion of an excess proton is correlated with fluctuations in the surrounding protein and solvent matrix, which may be rare on the picosecond and subpicosecond time scales of molecular motions. It is found that several active site residues, which do not directly participate in the proton transport event, have a significant impact on the dynamics of the excess proton. These secondary participants are shown to strongly influence the active site environment, resulting in the creation of water clusters that are conducive to fast, moderately slow, or slow proton transport events. The identification and characterization of these secondary participants illuminates the role of protein dynamics in the catalytic efficiency of HCA II.

Functional imaging for regenerative medicine.

In vivo imaging is a platform technology with the power to put function in its natural structural context. With the drive to translate stem cell therapies into pre-clinical and clinical trials, early selection of the right imaging techniques is paramount to success. There are many instances in regenerative medicine where the biological, biochemical, and biomechanical mechanisms behind the proposed function of stem cell therapies can be elucidated by appropriate imaging. Imaging techniques can be divided according to whether labels are used and as to whether the imaging can be done in vivo. In vivo human imaging places additional restrictions on the imaging tools that can be used. Microscopies and nanoscopies, especially those requiring fluorescent markers, have made an extraordinary impact on discovery at the molecular and cellular level, but due to their very limited ability to focus in the scattering tissues encountered for in vivo applications they are largely confined to superficial imaging applications in research laboratories. Nanoscopy, which has tremendous benefits in resolution, is limited to the near-field (e.g. near-field scanning optical microscope (NSNOM)) or to very high light intensity (e.g. stimulated emission depletion (STED)) or to slow stochastic events (photo-activated localization microscopy (PALM) and stochastic optical reconstruction microscopy (STORM)). In all cases, nanoscopy is limited to very superficial applications. Imaging depth may be increased using multiphoton or coherence gating tricks. Scattering dominates the limitation on imaging depth in most tissues and this can be mitigated by the application of optical clearing techniques that can impose mild (e.g. topical application of glycerol) or severe (e.g. CLARITY) changes to the tissue to be imaged. Progression of therapies through to clinical trials requires some thought as to the imaging and sensing modalities that should be used. Smoother progression is facilitated by the use of comparable imaging modalities throughout the discovery and trial phases, giving label-free techniques an advantage wherever they can be used, although this is seldom considered in the early stages. In this paper, we will explore the techniques that have found success in aiding discovery in stem cell therapies and try to predict the likely technologies best suited to translation and future directions.

Numerical simulation of multiple CME‐driven shocks in the month of 2011 September

AbstractA global, three‐dimensional (3‐D) numerical simulation model has been employed to study the Sun‐to‐Earth propagation of multiple (12) coronal mass ejections (CMEs) and their associated shocks in September 2011. The inputs to the simulation are based on actual solar observations, which include the CME speeds, source locations, and photospheric magnetic fields. The simulation result is fine tuned with in situ solar wind data observations at 1 AU by matching the arrival time of CME‐driven shocks. During this period three CME‐driven interplanetary (IP) shocks induced three sizable geomagnetic storms on 9, 17, and 26 September, with Dst values reaching −69, −70, and −101 nT, respectively. These storm events signify the commencement of geomagnetic activity in the solar cycle 24. The CME propagation speed near the Sun (e.g., < 30 RS) has been widely used to estimate the interplanetary CME (ICME)/Shock arrival time at 1 AU. Our simulation indicates that the background solar wind speed, as expected, is an important controlling parameter in the propagation of IP shocks and CMEs. Prediction of the ICME/shock arrival time at 1 AU can be more problematic for slow (e.g., < 500 km s−1) than fast CMEs (>1000 km s−1). This is because the effect of the background solar wind is more pronounced for slow CMEs. Here we demonstrate this difficulty with a slow (400 km s−1) CME event that arrived at the Earth in 3 days instead of the predicted 4.3 days. Our results also demonstrate that a long period (a month in this case) of simulation may be necessary to make meaningful solar source geomagnetic storm associations.

Mechanism of Strong Membrane Binding by Synaptotagmin 7 C2A Domain: Insight from Mutation and Lipid Composition Dependence

Synaptotagmins are membrane trafficking proteins that contain two C-terminal C2 domains, C2A and C2B. In eight of the seventeen mammalian isoforms, the C2 domains serve as calcium-dependent membrane binding motifs that trigger exocytosis upon cellular calcium influx. C2 domains from the different isoforms display different kinetics and affinities for membranes, which reflect their functions in a variety of different cell types. For example, synaptotagmin-7 (Syt7) is mainly active in slow secretion events such as insulin release. Previous work in our lab has shown that the C2A domain of human Syt7 has membrane association and dissociation rates that are ∼2 and ∼60-fold slower than the corresponding domain of Syt1, an isoform involved in rapid neurotransmitter release [Brandt DS, et al., Biochemistry; 51(39):7654-7664.] The purpose of this study is to investigate the balance of forces governing the stronger membrane binding of Syt7 C2A. We have used kinetic measurements of association and dissociation to assess membrane affinity, while systematically varying buffer composition, liposome size, lipid composition, and mutant forms of the protein domain. The results indicate that this domain's unusually strong membrane binding strength is due to a combination of electrostatics and the hydrophobic effect. In particular, dissociation rates are governed mainly by the hydrophobic effect, as seen by slower dissociation in the presence of the kosmotropic agent trehalose. Furthermore, the F167 residue in the Syt7 C2A domain acts as a secondary hydrophobic anchor for the membrane-docked protein domain, as its mutation to methionine (as in Syt1) results in a reproducible 2-fold increase in off rate.

Iterative Covariance-Based Removal of Time-Synchronous Artifacts: Application to Gastrointestinal Electrical Recordings.

The aim of this study was to develop, validate, and apply a fully automated method for reducing large temporally synchronous artifacts present in electrical recordings made from the gastrointestinal (GI) serosa, which are problematic for properly assessing slow wave dynamics. Such artifacts routinely arise in experimental and clinical settings from motion, switching behavior of medical instruments, or electrode array manipulation. A novel iterative Covariance-Based Reduction of Artifacts (COBRA) algorithm sequentially reduced artifact waveforms using an updating across-channel median as a noise template, scaled and subtracted from each channel based on their covariance. Application of COBRA substantially increased the signal-to-artifact ratio (12.8 ± 2.5 dB), while minimally attenuating the energy of the underlying source signal by 7.9% on average ( -11.1 ± 3.9 dB). COBRA was shown to be highly effective for aiding recovery and accurate marking of slow wave events (sensitivity = 0.90 ± 0.04; positive-predictive value = 0.74 ± 0.08) from large segments of in vivo porcine GI electrical mapping data that would otherwise be lost due to a broad range of contaminating artifact waveforms. Strongly reducing artifacts with COBRA ultimately allowed for rapid production of accurate isochronal activation maps detailing the dynamics of slow wave propagation in the porcine intestine. Such mapping studies can help characterize differences between normal and dysrhythmic events, which have been associated with GI abnormalities, such as intestinal ischemia and gastroparesis. The COBRA method may be generally applicable for removing temporally synchronous artifacts in other biosignal processing domains.

Distinct and competing interneuron populations can generate fast and slow gamma in oscillatory models of CA1

Gamma oscillations are widely observed in the mammalian brain and are important markers for cognition and attention [1,2]. In CA1 of the hippocampus of freely moving rats, power in one of two distinct oscillatory bands in the gamma regime (fast gamma and slow gamma) is predominantly present at a given moment of time [3]. Here, we demonstrate that models of networks with competing interneuron populations with different post-synaptic effects can create distinct oscillatory regimes that mimic the observed oscillations of CA1. Our network formulation reflects the following facts: 1) The duration of post-synaptic effect of an interneuron strongly influences the frequency in biophysical models of gamma oscillations [4]. 2) The primary CA1 inputs from CA3 and the entorhinal cortex (EC) preferentially innervate interneurons of different subtype with different post-synaptic durations [5,6]. We show that a firing rate model with competing interneuron populations with different post-synaptic time-constants is sufficient to generate slow and fast gamma oscillations. We conclude that mutual inhibition between the modeled interneuron populations permits switching in a bistable regime between distinct fast and slow gamma states. We also find similar behavior in spike-based network models. Our models explicitly predict the following about CA1: 1) Different interneurons innervated by different upstream regions phase-lock to different gamma states. 2) One population of interneurons is silenced, and another is active during fast and slow gamma events. 3) Mutual inhibition between interneuron populations is necessary for spontaneous switching of gamma state. Using experimental electrophysiological data from awake behaving rodents, we find interneurons that satisfy conditions 1 and 2, and we show putative 'fast' and 'slow' gamma interneurons categorized by their tendency to fire and phase-lock with oscillatory events as measured by a nearby local field potential. Our 3-population firing rate model is schematized in Figure ​Figure1A.1A. The dynamic variables are synaptic currents of an excitatory, fast inhibitory (IF) and slow inhibitory (Is) population; the firing rates are instantaneous functions of total input current. Fast excitation that interacts with inhibitory subpopulations supports oscillations. This interaction engages either one or both inhibitory subpopulations depending on IS - IF connectivity and input balance (Example in Figure ​Figure1B).1B). This network oscillates at biophysically realistic frequencies given biophysically realistic network parameters. The fast inhibitory population, IF and slow inhibitory population, IS have post-synaptic time-constants of 5ms and 15ms, respectively. These roughly capture the diversity of post-synaptic inhibitory current time-courses of interneurons of different subtypes measured in CA1 [6]. Our firing rate model demonstrates that with sufficient mutual inhibition between inhibitory populations, the oscillating network bifurcates into two stable regimes that oscillate at roughly the same frequencies as the observed fast and slow gamma oscillations [3,7]. Figure 1 A. Connectivity scheme for firing-rate two-gamma model. CA3 and EC denote inputs, E denotes excitatory population, and IF and IS denote the interneuron populations with brief and long post-synaptic effects, respectively. B. Graph shows the oscillation ... Previous experimental work suggests these two gamma oscillations reflect different information processing modes in the learning and memory system [7]. Our models provide a mechanistic understanding of these modes and posit a new oscillatory role for distinct interneurons in CA1. Moreover, our models describe general oscillatory behavior in networks with distinct interneuron populations.

Enhanced emissions in Tb3+-doped oxyfluoride scintillating glass ceramics containing KLu2F7 nano-crystals

KLu2F7: Tb3+ oxyfluoride glass ceramics (GC) were successfully manufactured via traditional melt-quenching route with further heat-treatment. Their micro-structural and optical properties were systemically investigated by XRD, TEM, HRTEM techniques, transmittance spectra, excitation spectra, emission spectra, luminescence lifetime measurements and X-ray excited luminescence (XEL). Both photoluminescence and XEL of KLu2F7 GC doped with Tb3+ are highly enhanced after further heat-treatment resulting from the partition of Tb3+ ions into the KLu2F7 crystalline lattice with low phonon energy. Our investigation suggests that such Tb3+-doped transparent KLu2F7 glass ceramics may present potential application in X-ray scintillator for slow event detection.

Extending the automated gastrointestinal analysis pipeline: Removal of invalid slow wave marks in gastric serosal recordings.

Gastric contractions are governed by a bioelectrical event known as slow waves. High-resolution electrical mapping has recently been applied to study complex gastric slow wave spatiotemporal propagations in detail. As these methods are translated to clinical and experimental applications, it is evident that efficient and automated methods are a necessity for analysis. Despite automated methods to detect slow wave events, manual review and correction remains necessary due to the presence of experimental noise in the recordings. Manual deletion of invalid slow wave events is time consuming and inefficient. We have therefore developed an algorithm to eliminate invalid markers of slow waves, via the use of frequency and morphological analysis. The techniques were validated with experimental data using serosal gastric slow wave recordings from animals and humans with a sensitivity of 90% and specificity of 85%. It is anticipated these methods will facilitate analyzing high-resolution slow wave mapping data and accelerate clinical translation of electrical mapping to clinical and diagnostic gastroentrology.

Detection of the Recovery Phase of in vivo gastric slow wave recordings.

Gastric motility is coordinated by bio-electrical events known as slow waves. Abnormalities in slow waves are linked to major functional and motility disorders. In recent years, the use of high-resolution (HR) recordings have provided a unique view of spatiotemporal activation profiles of normal and dysrhythmic slow wave activity. To date, in vivo studies of gastric slow wave activity have primarily focused on the activation phase of the slow wave event. In this study, the recovery phase of slow waves was investigated through the use of HR recording techniques. The recovery phase of the slow wave event was detected through the use of the signal derivative, computed via a wavelet transform. The activation to recovery interval (ARi) metric was computed as a difference between the recovery time and activation time. The detection method was validated with synthetic slow wave signals of varying morphologies with the addition of synthetic ventilator and high frequency noise. The methods was then applied to HR experimental porcine gastric slow wave recordings. Ventilator noise more than 10% of the slow wave amplitude affected the estimation of the ARi metric. Signal to noise ratio below 3 dB affected the ARi metric, but with minor deviation in accuracy. Experimental ARi values ranged from 3.7-4.7 s from three data sets, with significant differences across them.

Impact of climate change on agriculture, livestock and living environment in the Southeastern Part of Bangladesh

Bangladesh is one of a disaster prone countriy in the world. About 80% of coastal lands in Bangladesh are annually flooded during the rainy season. It is anticipated that Climate Change through the rise of sea level, will intensify flooding and inundation in the coastal areas of the country. Many geophysical, biological and social systems become imbalanced and are at risk because of climate change. Climate change is a main challenge for agricultural productivity which is anticipated and influenced to affect crop and livestock production by extreme events like drought, floods and storms. It will change the types and frequencies of various crops and livestock, availability of irrigation water supplies and the severity of soil erosion. Climate change risks can be distinguished into two classes. Sudden arrival risks emerge quickly such as flooding or hurricanes and the chronic risks are very slow events that are noticeable by society such as drought or sea level rise. Because of this climate change, social threat focuses on those demographic and socioeconomic factors that increase the impacts of hazard events on local populations (Tierney et al. 2001; Heinz Center 2002). Within the above backdrop, this paper intends to focus the impacts of climate change on agriculture, livestock and living environment of the people in the southeastern part of Bangladesh spesially Jessore, Satkhira, Khulna Mongla Bagerhat and Sundarban.

Preceding seismic activity and slow slip events in the source area of the 2011 Mw 9.0 Tohoku-Oki earthquake: a review

The 2011 Tohoku-Oki earthquake ruptured a large area of the megathrust east of NE Japan. The earthquake’s magnitude was 9.0, substantially larger than predicted. It is important to know what occurred in the source area prior to this great megathrust earthquake to improve understanding of the nucleation processes of large earthquakes and risk assessments in subduction zones. Seafloor observation data revealed the existence of two extremely large slip patches: one just updip of the mainshock hypocenter and the other 80–100 km to the north near the trench axis. For 70–90 years before 2003, M > 6 events and slips of M > c. 7 events on the megathrust occurred in the areas surrounding these two large slip patches. Seismic activity had increased since at least 2003 in the downdip portion of the source area of the Tohoku-Oki earthquake. In addition, long-term accelerated slow slip occurred in this downdip portion of the source area in the decades before the Tohoku-Oki earthquake. About 1 month before the earthquake, a slow slip event (SSE) took place at relatively shallow depths between the two large slip patches, accompanied by foreshock activity. Both the slow slip and foreshocks propagated from north to south toward the southern large slip patch. Two days before the earthquake, an M 7.3 foreshock and an associated postseismic slip began at relatively deep depths in the megathrust between the two large slip patches. In addition, a slow slip type event seems to have occurred approximately half a day after the M 7.3 foreshock near the mainshock hypocenter. This slow slip event and the foreshock activity again propagated from north to south toward the mainshock hypocenter. These long- and short-term preceding seismic and aseismic slip gradually reduced the interplate coupling, increased shear stresses at the two large slip patches (i.e., two strong asperity patches), and finally led to the rupture of the great Tohoku-Oki earthquake.

A taste of ethical consumption at a slow food festival

This paper examines the motives and experiences of attendees at a Slow Food festival to gain an understanding of how people engage with ethical consumer projects. Slow Food is a global social movement aimed at promoting food that is regionally, ethically, and sustainably produced, and convivially consumed. The movement uses culinary tourist events, such as food festivals and farmers' markets, to promote its philosophy and attract new members. There have been no empirical studies of ethical consumption using a Slow Food event as a case study. This study uses an ethnographic approach and a framework of virtue ethics to explore the views of people attending a major Slow Food festival in the city of Melbourne, Australia. Semi-structured interviews were conducted in situ with 33 participants (19 consumers and 14 stallholders) to discover their rationales for attending the festival, and their perspectives on ethical consumption. Transcripts were coded and thematically analysed, resulting in three themes reflecting varying degrees of public virtues (altruistic motivations) and private virtues (personal wellbeing): the quest for virtuous lifestyles through ethical consumption, the importance of co-production, and the challenges of putting ethical consumer projects like Slow Food into daily practice. The findings reveal the manner in which virtue ethics affects foodways and highlights the contingent and challenging nature of practising ethical eating.