The era of the wandering mind? Twenty-first century research on self-generated mental activity

The first decade of the twenty-first century was characterized by renewed scientific interest in self-generated mental activity (activity largely generated by the individual, rather than in direct response to experimenters’ instructions or specific external sensory inputs). To understand this renewal of interest, we interrogated the peer-reviewed literature from 2003 to 2012 (i) to explore recent changes in use of terms for self-generated mental activity; (ii) to investigate changes in the topics on which mind wandering research, specifically, focuses; and (iii) to visualize co-citation communities amongst researchers working on self-generated mental activity. Our analyses demonstrated that there has been a dramatic increase in the term “mind wandering” from 2006, and a significant crossing-over of psychological investigations of mind wandering into cognitive neuroscience (particularly in relation to research on the default mode and default mode network). If our article concludes that this might, indeed, be the “era of the wandering mind,” it also calls for more explicit reflection to be given by researchers in this field to the terms they use, the topics and brain regions they focus on, and the research literatures that they implicitly foreground or ignore

Epicutaneous Immunization with Type II Collagen Inhibits both Onset and Progression of Chronic Collagen-Induced Arthritis

Epicutaneous immunization is a potential non-invasive technique for antigen-specific immune-modulation. Topical application of protein antigens to barrier-disrupted skin induces potent antigen-specific immunity with a strong Th2-bias. In this study, we investigate whether the autoimmune inflammatory response of chronic collagen-induced arthritis (CCIA) in DBA/1-TCR-beta Tg mice can be modified by epicutaneous immunization. We show that epicutaneous immunization with type II collagen (CII) inhibited development and progression of CCIA and, importantly, also ameliorated ongoing disease as indicated by clinical scores of disease severity, paw swelling and joints histology. Treated mice show reduced CII-driven T cell proliferation and IFN-gamma production, as well as significantly lower levels of CII-specific IgG2a serum antibodies. In contrast, CII-driven IL-4 production and IgE antibody levels were increased consistent with skewing of the CII response from Th1 to Th2 in treated mice. IL-4 production in treated mice was inversely correlated with disease severity. Moreover, T cells from treated mice inhibited proliferation and IFN-gamma production by T cells from CCIA mice, suggesting induction of regulatory T cells that actively inhibit effector responses in arthritic mice. The levels of CD4(+)CD25(+) T cells were however not increased following epicutaneous CII treatment. Together, these results suggest that epicutaneous immunization may be used as an immune-modulating procedure to actively re-programme pathogenic Th1 responses, and could have potential as a novel specific and simple treatment for chronic autoimmune inflammatory diseases such as rheumatoid arthritis

Near-field and far-field analysis of an azimuthally polarized slow Bloch mode microlaser

We report on the near- and far-field investigation of the slow Bloch modes associated with the G point of the Brillouin zone, for a honeycomb lattice photonic crystal, using near-field scanning optical microscopy (NSOM) and infra-red CCD camera. The array of doughnut-shaped monopolar mode (mode M) inside each unit cell, predicted previously by numerical simulation, is experimentally observed in the near-field by means of a metal-coated NSOM tip. In far-field, we detect the azimuthal polarization of the doughnut laser beam due to destructive and constructive interference of the mode radiating from the surface (mode TEM01*). A divergence of 2° for the laser beam and a mode size of (12.8 ± 1) μm for the slow Bloch mode at the surface of the crystal are also estimated. © 2010 Optical Society of America

Englacial Architecture of Lambert Glacier, East Antarctica

The analysis of englacial layers using radio-echo sounding data enables the characterisation and reconstruction of current and past ice-sheet flow. Despite the Lambert Glacier catchment being one of the largest in Antarctica, discharging ~16 % of East Antarctica&rsquo;s ice, its englacial architecture has been little analysed. Here, we present a comprehensive analysis of Lambert Glacier&rsquo;s englacial architecture using radio-echo sounding data collected by the Antarctica's Gamburtsev Province Project (AGAP) North survey. We used an &ldquo;internal-layering continuity index&rdquo; (ILCI) to characterise the internal architecture of the ice and identify four macro-scale ILCI zones with distinct glaciological contexts. Whilst the catchment is dominated by continuous englacial layering, disrupted or discontinuous layering is highlighted by the ILCI at both the onset of enhanced ice flow (defined here as &gt;15 ma&minus;1) and along the shear margin, revealing the transition from internal-deformation-controlled to basal-sliding-dominated ice flow. These zones are characterised by buckled and folded englacial layers which align with the current ice-flow regime, and which we interpret as evidence that the flow direction of the Lambert Glacier trunk has changed little, if at all, during the Holocene. However, disturbed englacial layers along a deep subglacial channel that does not correspond to modern ice-flow routing suggest that ice-flow change has occurred in a former tributary which fed Lambert Glacier from grid north. As large outlet systems such as Lambert Glacier are likely to play a vital role in the future drainage of the East Antarctic Ice Sheet, constraining their englacial architecture to reconstruct their past ice flow and assess basal conditions is important.</p

Weathering fluxes and sediment provenance on the SW Scottish shelf during the last deglaciation

The reconstruction of past ice sheet dynamics can shed a light on long-term ice stream activity, and in turn provide constraints on the response of modern ice sheets to climate change. The Hebrides Ice Stream (HIS) flowed across part of the western Scottish shelf to the shelf-break during the last glacial cycle and drained a large portion of the northern sector of the British Irish-Ice Sheet. To investigate the deglacial dynamics of the HIS following the Last Glacial Maximum, lead (Pb) isotope records were extracted from the FeMn oxyhydroxide and detrital fractions of recovered laminated glacimarine mud sequences to monitor the changing activity of HIS during its retreat. These provide timing and some source information of glacially weathered inputs to the marine environment. The FeMn oxyhydroxide fraction in the samples is dominated by allochthonous particles (pre-formed) and shows a marked decrease from radiogenic (≤ 20.05 206Pb/204Pb) at ~ 21 cal ka BP to less radiogenic Pb isotope compositions (~ 19.48) towards the Windermere Interstadial (15.4–13 ka). This decrease represents a reduction in the flux of subglacially-derived radiogenic Pb to the continental shelf is interpreted as being associated with the break-up of the ice-stream in western Scotland around that time. The Pb, Sr and Nd isotopic signatures of the detrital fraction indicate a preponderance of Moine-sourced fine sediments (originated from the NW Highlands) in the core locations from ~ 21 to 15 cal ka BP (Dimlington Stadial - Windermere Interstadial), most likely dictated by the orientation of ice flow, tidal and oceanic current directions and sediment delivery. In contrast, ice rafted debris in a ~ 21 cal ka BP old basal diamicton contains volcanic-derived material, suggesting different provenance for different grain sizes. The FeMn oxyhydroxide 208Pb/204Pb ratio shows an unusual inversion relative to the other Pb isotope ratios, and is attributed to the introduction of secondary weathering phases from a source with contrasting 208Pb/204Pb but similar 206Pb/204Pb and 207Pb/204Pb. In the detrital fraction, the inversions are constrained to periodic spikes, which may indicate an increased contribution from a high Th/U source, potentially the neighbouring Archaean amphibolitic Lewisian basement in the Outer Hebrides. This study demonstrates how geochemical investigation on continental shelves can be used to constrain the timing, activity and flow sources of palaeo-ice streams

Naive B cell output in HIV-infected and HIV-uninfected children.

In this study, we aimed to quantify KREC (kappa-deleting recombination excision circle) levels and naive B cell output in healthy HIV-uninfected children, compared with HIV-infected South African children, before and after starting ART (antiretroviral therapy). Samples were acquired from a Child Wellness Clinic (n = 288 HIV-uninfected South African children, 2 weeks-12 years) and the Children with HIV Early Antiretroviral Therapy (CHER) trial (n = 153 HIV-infected South African children, 7 weeks-8 years). Naive B cell output was estimated using a mathematical model combining KREC levels to reflect B cell emigration into the circulation, flow cytometry measures of naive unswitched B cells to quantify total body naive B cells, and their rates of proliferation using the intracellular marker Ki67. Naive B cell output increases from birth to 1 year, followed by a decline and plateau into late childhood. HIV-infected children on or off ART had higher naive B cell outputs than their uninfected counterparts (p = .01 and p = .04). This is the first study to present reference ranges for measurements of KRECs and naive B cell output in healthy and HIV-infected children. Comparison between HIV-uninfected healthy children and HIV-infected children suggests that HIV may increase naive B cell output. Further work is required to fully understand the mechanisms involved and clinical value of measuring naive B cell output in children

Extent and retreat history of the Barra Fan Ice Stream offshore western Scotland and northern Ireland during the last glaciation

During the Last Glacial Maximum (LGM) the marine-terminating Barra Fan Ice Stream (BFIS), a major conduit of the British Irish Ice Sheet (BIIS), drained much of western Scotland and northwest Ireland with ice streaming onto the continental shelf of the Malin Sea. The extent and retreat history of this ice stream across the shelf, until now, is not well known. In particular, geochronological constraints on the history of this ice stream have thus far been restricted to deep-sea cores or terrestrial cosmogenic nuclide dating onshore, with ages across the shelf absent. To understand the possible external forcing factors acting on this marine terminating ice stream during retreat, improved geochronological constraint on its deglaciation is necessary. Here, we present new geophysical data, marine sediment cores and over forty radiocarbon dates to provide important constraints on maximum extent of the BFIS, as well as the timing and pattern of retreat back across the Malin Shelf. Dated moraines and grounding-zone wedges (GZW) seen in seafloor sub-bottom profiles provide evidence that the BFIS reached the Malin Shelf edge during the LGM and was at its maximum extent around 26.7 ka BP. The presence of two sets of GZWs suggests that the style of retreat was episodic. The new radiocarbon chronology shows that retreat from the shelf edge was underway by 25.9 ka BP, with the majority of the continental shelf ice free by 23.2 ka BP, and that glacimarine conditions were present in the Sea of Hebrides by 20.2 ka BP at the latest. Collectively, these results indicate that the majority of the Malin Shelf was free of grounded ice by ∼21.5–20 ka BP, which is up to 4000 years earlier than previously reconstructed. We attribute this early deglaciation to high relative sea level caused by glacial isostatic depression when the BIIS reached its maximum extent promoting ice shelf and grounding line instability. Two deep troughs, forming reverse bed slopes, aided the continued retreat of the BFIS. This suggests that local ice loading and bed morphology can be significant controls on the destabilisation of a marine-terminating ice stream and can override the influence of ocean and atmospheric temperatures

Automated characterisation of glaciomarine sediments using X-ray computed laminography

This study investigates the potential of a new high-resolution, non-destructive, X-ray imaging technique for the Quaternary Sciences – computed laminography (CL). Greyscale properties are systematically extracted from digital X-radiographic CL images of cored glaciomarine sediments to analyse and characterise sediments at pixel-scale resolution (< 0.1 mm). We show how this can be achieved manually, and also with an easy-to-use, automated statistical tool which we have devised specifically for use in glaciomarine sediments. This Sediment Characteristics tool, in the form of a plugin for the freely available FIJI/ImageJ programme, extracts mean or median X-ray grey values (GV) – a proxy for sediment density; and associated standard deviation (SD) – a proxy for sediment heterogeneity – at sub-mm resolution, across the width of sediment core CL images. We demonstrate how these properties (GV and SD) can be directly used to characterise sediment properties and in particular to quantify the abundance of gravel clasts, or ice-rafted debris, in cored glaciomarine sediments. The tool’s effectiveness is compared with other, more traditional, X-radiographic methods for counting ice-rafted gravel clasts in glaciomarine sediment. We propose that the CL output and Sediment Characteristics tool also have the potential to quantitatively analyse other 3-dimensional structures, such as cyclic lamination (varve) geometry; deformation structures; bioturbation and void space (porosity). Finally, we present the raw code, allowing open-access, transparency and reproducibility in other formats

The Case against a Smoker's License

Tobacco continues to kill millions of people around the world each year and its use is increasing in some countries, which makes the need for new, creative, and radical efforts to achieve the tobacco control endgame vitally important. One such effort is discussed in this PLOS Medicine Debate, where Simon Chapman presents his proposal for a "smoker's license" and Jeff Collin argues against. Chapman sets out a case for introducing a smart card license for smokers designed to limit access to tobacco products and encourage cessation. Key elements of the smoker's license include smokers setting daily limits, financial incentives for permanent license surrender, and a test of health risk knowledge for commencing smokers. Collin argues against the proposal, saying that it would shift focus away from the real vector of the epidemic--the tobacco industry--and that by focusing on individuals it would censure victims, increase stigmatization of smokers, and marginalize the poor

Holocene history of the 79° N ice shelf reconstructed from epishelf lake and uplifted glaciomarine sediments

Acknowledgements This work was funded by a NERC standard grant (grant no. NE/N011228/1), and some radiocarbon analysis was funded by NEIF (grant NE/S011587/1; allocation number 2169.1118). We thank the Alfred Wegener Institute, particularly Angelika Humbert and Hicham Rafiq, for significant logistic support through the iGRIFF project. Additional support was provided by Station Nord (Jorgen Skafte), Nordlandair, Air Greenland, and the Joint Arctic Command. Naalakkersuisut (government of Greenland) provided scientific survey (VU-00121) and export (046/2017) licences for this work. Finally, we would like to thank our (Nanu Travel) field ranger Isak (and dog Ooni) for keeping us safe in the field and taking great pleasure in beating James A. Smith at cards. Financial support This research has been supported by the Natural Environment Research Council (grant no. NE/N011228/1).Peer reviewedPublisher PD