Magma fragmentation:a perspective on emerging topics and future directions

AbstractThe breaking apart of magma into fragments is intimately related to the eruptive style and thus the nature and footprint of volcanic hazards. The size and shape distributions of the fragments, in turn, affect the efficiency of heat transfer within pyroclastic plumes and currents and the settling velocity, and so the residence time, of particles in the atmosphere. Fundamental work relating the glass transition to the fragmentation of magmas remains at the heart of conceptual and numerical models of volcanic eruptions. Current fragmentation criteria, however, do not predict the sizes and shapes of the resulting fragments, or fully account for the multiphase nature of magmas or ways in which magma can break in a fluidal manner or by thermal stress. The pulsatory, non-steady state nature of some eruptions, and related interactions with these fragmentation criteria, also requires further investigation. Here, we briefly review some recent advances in the field of magma fragmentation and provide a perspective on how integrated field, experimental and numerical modelling studies can address key outstanding challenges.</jats:p

Rhythmic temporal structure at encoding enhances recognition memory

Presenting events in a rhythm has been shown to enhance perception and facilitate responses for stimuli that appear in synchrony with the rhythm, but little is known about how rhythm during encoding influences later recognition. In this study, participants were presented with images of everyday objects in an encoding phase prior to a recognition task in which they judged whether or not objects were previously presented. Blockwise, object presentation during encoding followed either a rhythmic (constant, predictable) or arrhythmic (random, unpredictable) temporal structure, of which participants were unaware. Recognition was greater for items presented in a rhythmic relative to an arrhythmic manner. During encoding, there was a Dm effect with larger positivity for rhythmic over arrhythmic stimuli. At recognition, memory specific ERP components were differentially affected by temporal structure: the FN400 old/new effect was unaffected by rhythmic structure, whilst the late positive component (LPC) old/new effect was observed only for rhythmically encoded items. Taken together, this study provides new evidence that memory specific processing at recognition is affected by temporal structure at encoding

ISGylation-independent protection of cell growth by USP18 following interferon stimulation

Type 1 interferon stimulation highly up-regulates all elements of a ubiquitin-like conjugation system that leads to ISGylation of target proteins. An ISG15-specific member of the deubiquitylase family, USP18, is up-regulated in a co-ordinated manner. USP18 can also provide a negative feedback by inhibiting JAK-STAT signalling through protein interactions independently of DUB activity. Here, we provide an acute example of this phenomenon, whereby the early expression of USP18, post-interferon treatment of HCT116 colon cancer cells is sufficient to fully suppress the expression of the ISG15 E1 enzyme, UBA7. Stimulation of lung adenocarcinoma A549 cells with interferon reduces their growth rate but they remain viable. In contrast, A549 USP18 knock-out cells show similar growth characteristics under basal conditions, but upon interferon stimulation, a profound inhibition of cell growth is observed. We show that this contingency on USP18 is independent of ISGylation, suggesting non-catalytic functions are required for viability. We also demonstrate that global deISGylation kinetics are very slow compared with deubiquitylation. This is not influenced by USP18 expression, suggesting that enhanced ISGylation in USP18 KO cells reflects increased conjugating activity.</p

Singing and music making: physiological responses across early to later stages of dementia

Background: Music based interventions have been found to improve wellbeing for people with dementia. More recently there has been interest in physiological measures to provide additional information about how music and singing impact this population. Methods: This multiple-case study design explored physiological responses (heart rate-HR, electrodermal activity-EDA, movement, and skin temperature-ST) of nine people with mild-to-moderate using simulation modelling analysis. Results: In study 1, the singing group showed an increase in EDA (p < 0.01 for 8/9 participants) and HR (p < 0.01 for 5/9 participants) as the session began. HR (p < 0.0001 for 5/9 participants) and ST (p < 0.0001 for 6/9 participants) increased during faster tempos. EDA (p < 0.01 all), movement (p < 0.01 for 8/9 participants) and engagement were higher during singing compared to a baseline control. In study 2 EDA (p < 0.0001 for 14/18 data points [3 music conditions across 6 participants]) and ST (p < 0.001 for 10/18 data points) increased and in contrast to the responses during singing, HR decreased as the sessions began (p < 0.002 for 9/18 data points). EDA was higher during slower music (p < 0.0001 for 13/18 data points), however this was less consistent in more interactive sessions than the control. There were no consistent changes in HR and movement responses during different music genre. Conclusions: Physiological measures provide valuable information about the experiences of people with dementia participating in musical activities, particularly for those with verbal communication difficulties. Future research should consider using physiological measures. video-analysis and observational measures to explore further how engagement in specific activities, wellbeing and physiology interact

Cocaine- and Amphetamine-Regulated Transcript (CART) Signaling within the Paraventricular Thalamus Modulates Cocaine-Seeking Behaviour

Background: Cocaine- and amphetamine-regulated transcript (CART) has been demonstrated to play a role in regulating the rewarding and reinforcing effects of various drugs of abuse. A recent study demonstrated that i.c.v. administration of CART negatively modulates reinstatement of alcohol seeking, however, the site(s) of action remains unclear. We investigated the paraventricular thalamus (PVT) as a potential site of relapse-relevant CART signaling, as this region is known to receive dense innervation from CART-containing hypothalamic cells and to project to a number of regions known to be involved in mediating reinstatement, including the nucleus accumbens (NAC), medial prefrontal cortex (mPFC) and basolateral amygdala (BLA). Methodology/Principal Findings: Male rats were trained to self-administer cocaine before being extinguished to a set criterion. One day following extinction, animals received intra-PVT infusions of saline, tetrodotoxin (TTX; 2.5 ng), CART (0.625 µg or 2.5 µg) or no injection, followed by a cocaine prime (10 mg/kg, i.p.). Animals were then tested under extinction conditions for one hour. Treatment with either TTX or CART resulted in a significant attenuation of drug-seeking behaviour following cocaine-prime, with the 2.5 µg dose of CART having the greatest effect. This effect was specific to the PVT region, as misplaced injections of both TTX and CART resulted in responding that was identical to controls. Conclusions/Significance: We show for the first time that CART signaling within the PVT acts to inhibit drug-primed reinstatement of cocaine seeking behaviour, presumably by negatively modulating PVT efferents that are important for drug seeking, including the NAC, mPFC and BLA. In this way, we identify a possible target for future pharmacological interventions designed to suppress drug seeking

Profiles of resilient psychosocial function during three isolated ski expeditions in the High Arctic

To successfully complete a Polar expedition individuals and teams must respond resiliently to the environmental, psychological, and social demands they face. In this study we examined profiles of resilient function in seven people from three expeditions in the High Arctic. Using a structured daily diary, participants reported on experiences of physical health (morning and evening), affect, team cohesion, performance, and potential explanatory factors including sleep, demand appraisals, events, and coping strategies. Notable intra- and inter-individual variability was observed in daily reports and all profiles could be interpreted as representing resilient function. A number of significant relationships were found between markers of resilient physical and psychosocial function and potential explanatory variables. For example, there was much more daily variability in an individual's reporting of positive affect than prior research might imply, and what prior research designs could capture. Further, while negative affect tended to remain low and stable, our findings reveal that even minor and infrequent increases in negative emotions were significantly associated with other variables in the network. Finally, across the expedition period individual coping resources consistently exceeded demands, suggesting that individuals viewed the expedition as a challenge and not a threat. More broadly, these findings inform efforts to monitor, and maintain resilience when operating in Polar and other extreme settings

Continuous subcutaneous insulin infusion alters microRNA expression and glycaemic variability in children with type 1 diabetes

To determine whether continuous subcutaneous insulin infusion (CSII) vs. multiple daily injections (MDI) therapy from near-diagnosis of type 1 diabetes is associated with reduced glycaemic variability (GV) and altered microRNA (miRNAs) expression. Adolescents (74% male) within 3-months of diabetes diagnosis (n = 27) were randomized to CSII (n = 12) or MDI. HbA1c, 1-5-Anhydroglucitol (1,5-AG), high sensitivity C-peptide and a custom TaqMan qPCR panel of 52 miRNAs were measured at baseline and follow-up (median (LQ-UQ); 535 (519-563) days). There were no significant differences between groups in baseline or follow-up HbA1c or C-peptide, nor baseline miRNAs. Mean +/- SD 1,5-AG improved with CSII vs. MDI (3.1 +/- 4.1 vs. - 2.2 +/- - 7.0 mg/ml respectively, P = 0.029). On follow-up 11 miRNAs associated with diabetes vascular complications had altered expression in CSII-users. Early CSII vs. MDI use is associated with lower GV and less adverse vascular-related miRNAs. Relationships with future complications are of interest